Stabilization methods for microbial-derived olefins

ABSTRACT

Processes and systems for stabilization and subsequent hydrogenation of an immiscible olefin are described. Methods of stabilizing a microbial-derived olefin composition are also described.

RELATED APPLICATIONS

This application claims priority to U.S. provisional application Nos.61/166,185 filed Apr. 2, 2009 and 61/249,900 filed Oct. 8, 2009. Thedisclosures of the above referenced applications are incorporated byreference herein in their entireties.

FIELD

Provided herein are processes and systems for stabilization andsubsequent hydrogenation of microbial-derived olefins.

BACKGROUND

Petroleum-derived compounds and compositions are found in a variety ofproducts ranging from plastics to household cleaners as well as fuels.Given the environmental impact of these compositions, there is anincreasing demand for more renewable and sustainable alternatives.

With recent advances in metabolic engineering, biology is providingviable alternatives to petroleum-derived compounds and compositions. Forexample, isoprenoids comprise a diverse class of compounds with over50,000 members, and have a variety of uses including as specialtychemicals, pharmaceuticals and even fuels. Most isoprenoid compoundsconventionally have been synthesized from petroleum sources or extractedfrom plant sources. Now, a third option exists which is capable ofmaking a desired isoprenoid compound using microbial cells. Systems formaking petroleum-derived compounds and compositions have been described,for example, by U.S. Pat. No. 7,399,323; U.S. Patent Publication No.2008/0274523; and PCT Publication Nos. WO 2007/140339, WO 2008/140492,WO 2008/133658, and WO 2009/014636.

However, in order for a microbial-derived compound to be competitive, itshould be made more cost effectively than a comparable compound obtainedfrom naturally occurring sources. As a result, methods for obtaining themost optimal yield of a desired compound are needed. Such methods areprovided herein.

SUMMARY

Provided herein is a method of stabilizing a microbial-derived olefincomprising separating immiscible olefin from a mixture comprising anaqueous solution, microbial cells and immiscible olefin thereby forminga crude olefin composition; purifying the crude olefin compositionthereby forming a purified olefin composition; and adding a phenolicantioxidant to the purified olefin composition to form a stabilizedpurified microbial-derived olefin composition. In certain embodiments,the purification step is selected from fractional distillation, flashdistillation, adsorption, liquid chromatography, solvent extraction anda combination thereof. In certain embodiments, the immiscible olefincomprises farnesene.

In another aspect, provided herein is a stabilized microbial olefincomposition comprising an immiscible olefin in an amount at least about93% by weight of the composition; and a phenolic antioxidant in anamount at least about 0.0001% by weight of the composition. In oneembodiment, a stabilized microbial olefin composition comprises animmiscible olefin in an amount at least about 93% by weight of thecomposition; and a phenolic antioxidant in an amount from about0.0001-0.5% by weight of the composition. In one embodiment, astabilized microbial olefin composition comprises an immiscible olefinin an amount at least about 93% by weight of the composition; and aphenolic antioxidant in an amount from about 0.0001-0.1%, 0.0005-0.1%,0.0005-0.01%, 0.0005-0.05 or 0.001 to 0.01% by weight of thecomposition. In another aspect, provided herein is a stabilizedmicrobial olefin composition comprising an immiscible olefin in anamount at least about 93% by weight of the composition; and a phenolicantioxidant in an amount at least about 0.001% by weight of thecomposition.

In certain embodiments, provided herein is a method for hydrogenation ofan immiscible olefin comprising reacting an immiscible olefin withhydrogen in the presence of a hydrogenation catalyst such that hydrogensaturates at least one double bond in the immiscible olefin and whereinthe hydrogenation reaction occurs at room temperature or highertemperature. In certain embodiments, the hydrogenation reaction providedherein occurs a temperature that is 20° C. or greater. In certainembodiments, the hydrogenation reaction provided herein occurs atemperature of about 20° C., 30° C., 40° C., 50° C., 60° C., 70° C., 80°C., 90° C., 100° C. or greater. In certain embodiments, thehydrogenation reaction provided herein occurs a temperature from about20-100° C., 40-100° C., 50-100° C., 75-100° C., 90-100° C., 90-125° C.,80-125° C. or greater. In certain embodiments, provided herein is amethod for hydrogenation of an immiscible olefin comprising reacting animmiscible olefin with hydrogen in the presence of a hydrogenationcatalyst such that hydrogen saturates at least one double bond in theimmiscible olefin and wherein the hydrogenation reaction occurs at atemperature greater than about 100° C. In certain embodiments, thehydrogenation reaction is conducted in a fixed bed reactor.

In one aspect, provided herein is a method for hydrogenating animmiscible olefin comprising: a) providing a feed stream to the inlet ofa fixed bed reactor wherein the feed stream comprises an immiscibleolefin and a diluent composition; b) contacting the feed stream withhydrogen in the presence of a hydrogenation catalyst at a temperaturegreater than about 100° C. thereby producing an effluent; c) separatingthe effluent which comprises a hydrogenated immiscible olefin into aproduct stream comprising a hydrogenated immiscible olefin and a recyclestream comprising a hydrogenated immiscible olefin; d) adding therecycle stream as part of the diluent composition to a stream comprisingthe immiscible olefin to form a feed stream comprising recycledhydrogenated immiscible olefin; e) providing the feed stream comprisingrecycled hydrogenated immiscible olefin to the inlet of the fixed bedreactor; and f) repeating steps b)-e) at least once.

In certain embodiments, provided herein is a purified farnesenecomposition comprising a microbial-derived mixture comprising farnesenein an amount that is equal to or greater than about 93% by weight andthe following compounds each of which is present in an amount that isequal to or greater than about 0.1% by weight: bisabolene, zingiberene,farnesol, and farnesene epoxide; and a phenolic antioxidant in an amountthat is at least about 0.001% by weight.

In certain embodiments, provided herein are processes and systems forcatalytic hydrogenation of farnesene to obtain farnesane. In one aspect,provided herein is a process for hydrogenation of farnesene bycontacting a farnesene feed and hydrogen with a catalyst.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a plot of the rate of hydrogenation versus hydrogenequivalents during a hydrogenation reaction of commercially availabletrans-β farnesene (Bedoukian Research). In the plot, data forhydrogenation of trans-β farnesene with α-tocopherol is represented by♦, data for hydrogenation of trans-β farnesene without α-tocopherol isrepresented by ▴, and data for hydrogenation of trans-β farnesenewithout α-tocopherol plus additional purification from silica filtrationto remove impurities is represented by x and ▪, respectively. The rateof observed hydrogenation as a function of hydrogen equivalent appearsto be limited by the α-tocopherol added by Bedoukian to stabilizefarnesene.

FIG. 2 is a plot comparing rate versus hydrogen equivalent for two lotsof commercially available farnesene that were silica filtered to removeα-tocopherol, represented by ♦ and ▪ in the plot, along with acommercially available lot of farnesene that was silica filtered toremove α-tocopherol, stored at 20° C. for ten days and thenhydrogenated, represented by ▴. The hydrogenation reaction proceededwith an average value of 10.7±1.9 minutes per hydrogen equivalent (9.3minutes per hydrogen equivalent, data represented by ♦ in the plot, and12.1 minutes per hydrogen equivalent, data represented by ▪ in the plot,individually). The hydrogenation rate of commercially availablefarnesene in which α-tocopherol was removed, stored at 20° C. for tendays, and then hydrogenated (data represented by ▴ in the plot) was 14.9minutes per hydrogen equivalent. The hydrogenation conditions were 5%Pd/C at 60 psia at 100° C.

FIGS. 3A and 3B are plots of rate and temperature versus hydrogenequivalents during a hydrogenation reaction of microbially-derivedfarnesene and commercially available farnesene (with α-tocopherolremoved), respectively, under identical reaction conditions (5% Pd/C at60 psia at 100° C.). In the plot, data for rate is represented by ♦,data for temperature is represented by ●.

FIG. 4 is a plot showing the hydrogenation time/hydrogen equivalentversus storage time for various lots of microbial-derived farnesene at4° C. The hydrogenation conditions were 5% Pd/C at 60 psia at 100° C. Inthe plot, data for crude farnesene composition is represented by ♦, datafor silica filtered farnesene composition is represented by ▪, and datafor crude farnesene composition with 100 ppm 4-tert-butylcatechol isrepresented by ▴.

FIG. 5 is a plot showing peroxide concentration and hydrogenationtime/hydrogen equivalent versus storage time for various lots ofmicrobial-derived farnesene at 4° C. The hydrogenation conditions were5% Pd/C at 60 psia at 100° C. In the plot, dotted lines representhydrogenation rates and solid lines represent peroxide concentration.The data for crude farnesene composition is represented by ♦, data forsilica filtered farnesene composition is represented by ▪, and data forpurified farnesene composition with 100 ppm 4-tert-butylcatechol isrepresented by ▴.

FIG. 6 is a plot of apparent hydrogenation rates for farnesene at 0.5,1, 2, and 3 equivalents of hydrogen at 100° C. and 50 mg of catalystloading.

FIG. 7 is a plot of hydrogenation uptake rate for various purifiedolefin compositions over periods of time to test catalyst life at theprocess LHSV (Liquid Hourly Space Velocity) of 12 ml of olefin fed toprocess/mL catalyst per hour. The hydrogenation conditions were: 20%Ni/Al₂O₃ catalyst diluted 4× with glass beads hydrogenating acomposition of 5% farnesene and 95% decane at a pressure of 500 psig. Inthe first part of the plot, the farnesene in the farnesene compositionis a purified microbial-derived farnesene and the hydrogenation reactionoccurs at 100° C. As it can be seen, the catalyst degrades rapidly overone day and continues to deactivate over three days. This catalyst couldbe recovered by increasing the temperature. This is shown by the secondpart of the plot which shows that the hydrogen uptake can be recoveredalmost fully by simply increasing the temperature to a temperaturegreater than 100° C. (in this case 150° C.). The third part of the plotdemonstrates catalyst deactivation as the chemically-derived counterpartcould be hydrogenated at 100° C. with no catalyst deactivation.

FIG. 8 is a plot of hydrogenation uptake rate for farnesene versusfarnesene concentration showing that hydrogenation of farnesene displayszero-order kinetics and no substrate mass transfer resistance.

FIG. 9 is a schematic of an exemplary hydrogenation system for thepractice of an embodiment of the hydrogenation process provided herein.

FIG. 10 shows the final product composition from various hydrogenationsof limonene in a batch reactor.

DETAILED DESCRIPTION

Terminology

As used herein, “microbial-derived olefin” refers a compound with atleast one double bound that is made by microbial cells (both recombinantas well as naturally occurring). In certain embodiments, themicrobial-derived olefin is a hydrocarbon with at least onecarbon-carbon double bond. In certain embodiments, the microbial-derivedolefin is an isoprenoid. In certain embodiments, the microbial-derivedolefin is a C₅-C₂₀ isoprenoid. In certain embodiments, themicrobial-derived olefin is a C₁₀-C₁₅ isoprenoid. In furtherembodiments, the microbial-derived olefin is an isoprenoid with at leastone carbon-carbon double bond. In additional embodiments, themicrobial-derived olefin is a C₅-C₂₀ isoprenoid or a C₁₀-C₁₅ isoprenoidwith at least one carbon-carbon double bond.

As used herein, “immiscible olefin” refers to a microbial-derived olefinthat is immiscible with water.

As used herein, “crude olefin composition” refers to a compositioncomprising an immiscible olefin wherein the olefin is present in thecomposition in an amount greater than about 50% by weight but is lessthan about 92% by weight.

As used herein, “purified olefin composition” refers to a compositioncomprising an immiscible olefin wherein the olefin is present in thecomposition in an amount equal to or greater than about 93% by weight.In certain embodiments, the olefin is present in an amount equal to orgreater than about 95% by weight.

As used herein, “stabilized purified olefin composition” refers to acomposition comprising a purified olefin composition and a phenolicantioxidant.

As used herein, “phenolic antioxidant” refers to an antioxidant that isa phenol or a phenol derivative, wherein the phenol derivative containsan unfused phenyl ring with one or more hydroxyl substitutents. The termalso includes polyphenols. Illustrative examples of a phenolicantioxidant include: resveratrol; 3-tert-butyl-4-hydroxyanisole;2-tert-butyl-4-hydroxyanisole; 4-tert-butylcatechol (which is also knownas TBC); 2,4-dimethyl-6-tert-butylphenol; and2,6-di-tert-butyl-4-methylphenol (which is also known asbutylhydroxytoluene or BHT). Additional examples of phenolicantioxidants are disclosed in U.S. Pat. No. 7,179,311.

As used herein, “hydrogenated immiscible olefin” refers to a partiallyhydrogenated immiscible olefin. In other words, an immiscible olefinthat had a plurality of double bonds wherein at least one of its doublebonds has been hydrogenated leaving at least one double bond remaining.

As used herein, “saturated immiscible olefin” refers to a fullyhydrogenated counterpart of an immiscible olefin.

“α-Farnesene” refers to a compound having the following structure:

or an isomer thereof. In certain embodiments, the α-farnesene comprisesa substantially pure isomer of α-farnesene. In certain embodiments, theα-farnesene comprises a mixture of isomers, such as cis-trans isomers.In further embodiments, the amount of each of the isomers in theα-farnesene mixture is independently from about 0.1 wt. % to about 99.9wt. %, from about 0.5 wt. % to about 99.5 wt. %, from about 1 wt. % toabout 99 wt. %, from about 5 wt. % to about 95 wt. %, from about 10 wt.% to about 90 wt. %, from about 20 wt. % to about 80 wt. %, based on thetotal weight of the α-farnesene mixture.

“β-Farnesene” refers to a compound having the following structure:

or an isomer thereof. In certain embodiments, the β-farnesene comprisesa substantially pure isomer of β-farnesene. In certain embodiments, theβ-farnesene comprises a mixture of isomers, such as cis-trans isomers.In further embodiments, the amount of each of the isomers in theβ-farnesene mixture is independently from about 0.1 wt. % to about 99.9wt. %, from about 0.5 wt. % to about 99.5 wt. %, from about 1 wt. % toabout 99 wt. %, from about 5 wt. % to about 95 wt. %, from about 10 wt.% to about 90 wt. %, from about 20 wt. % to about 80 wt. %, based on thetotal weight of the β-farnesene mixture.

“Farnesene” refers to α-farnesene, β-farnesene or a mixture thereof.

“Hydrogenated farnesene” refers to α-farnesene, β-farnesene or a mixturethereof wherein at least one double bond is hydrogenated. Thus,hydrogenated farnesene emcompasses, for example, α-farnesene whereinone, two, three or four double bonds are hydrogenated, β-farnesenewherein one, two, three or four double bonds are hydrogenated, and amixture thereof. Hydrogenated farnesene is obtained by partialhydrogenation of farnesene.

“Farnesane” refers to a compound having structure:

or a stereoisomer thereof. In certain embodiments, the farnesanecomprises a substantially pure stereoisomer of farnesane. In certainembodiments, the farnesane comprises a mixture of stereoisomers, such asenantiomers and diastereoisomers, of farnesane. In further embodiments,the amount of each of the stereoisomers in the farnesane mixture isindependently from about 0.1 wt. % to about 99.9 wt. %, from about 0.5wt. % to about 99.5 wt. %, from about 1 wt. % to about 99 wt. %, fromabout 5 wt. % to about 95 wt. %, from about 10 wt. % to about 90 wt. %,from about 20 wt. % to about 80 wt. %, based on the total weight of thefarnesane mixture.

As used herein, “unsaturated farnesane” refers to one or more farnesanemolecules containing one or more double bonds. For example,monounsaturated farnesane refers to one or more farnesane moleculescontaining one double bond. Unsaturated farnesane is obtained by partialhydrogenation of farnesene.

“Farnesene epoxide refers to a compound having structure:

or an isomer thereof.

“Farnesol refers to a compound having the structure:

or an isomer thereof.

“Limonene” refers to a compound having the structure

or an isomer thereof.

“Zingiberene” refers to a compound having the following structure:

or an isomer thereof.

“Bisabolene” refers to a compound having the following structure:

or an isomer thereof.

“Bisabolane” refers to a compound having the following structure:

or an isomer thereof.

As used herein, “farnesene feed” refers to a mixture of farnesene and adiluent, such as farnesane.

As used herein, “product fraction” refers to a fraction of a productcomposition comprising a hydrogenated immiscible olefin, such ashydrogenated farnesene, that is separated from an effluent of ahydrogenation reaction provided herein. Optionally, the product fractioncan undergo further hydrogenation in a secondary reactor to removeresidual unsaturation to obtain a saturated product, e.g., farnesane, orcan be used without further hydrogenation, for example in biofuels,without further treatment.

As used herein, “reactant stream” refers to a mixture of an immiscibleolefin feed and hydrogen.

As used herein and unless otherwise indicated, the term “process(es)”refers to method(s) disclosed herein that is (are) useful forhydrogenation of a microbial-derived olefin where at least one doublebond of the olefin is converted into a single bond by the addition ofhydrogen. Modifications to the methods disclosed herein (e.g., startingmaterials, reagents, temperatures, pressure) are also encompassed.

As used herein, “recycling fraction” refers to a fraction of a productcomposition that is separated from an effluent of a hydrogenationreaction provided herein and recycled as a diluent in the hydrogenationreaction.

As used herein and unless otherwise indicated, a reaction that is“substantially complete” or is driven to “substantial completion” meansthat the reaction contains more than about 80% desired product bypercent yield, more than about 90% desired product by percent yield,more than about 95% desired product by percent yield, or more than about97% desired product by percent yield.

As used herein, “axial temperature rise” refers to the increase intemperature during a hydrogenation reaction in a cocurrent downflowreactor as a reactant stream flows from the top of the reactor to thebottom of the reactor in presence of a catalyst.

In the following description, all numbers disclosed herein areapproximate values, i regardless whether the word “about” or“approximate” is used in connection therewith. Numbers may vary by 1percent, 2 percent, 5 percent, or, sometimes, 10 to 20 percent. Whenevera numerical range with a lower limit, R^(L), and an upper limit, R^(U),is disclosed, any number falling within the range is specificallydisclosed. In particular, the following numbers within the range arespecifically disclosed: R=R^(L)+k*(R^(U)−R^(L)), wherein k is a variableranging from 1 percent to 100 percent with a 1 percent increment, i.e.,k is 1 percent, 2 percent, 3 percent, 4 percent, 5 percent, . . . , 50percent, 51 percent, 52 percent, . . . , 95 percent, 96 percent, 97percent, 98 percent, 99 percent, or 100 percent. Moreover, any numericalrange defined by two R numbers as defined in the above is alsospecifically disclosed.

The claimed subject matter can be understood more fully by reference tothe following detailed description and illustrative examples, which areintended to exemplify non-limiting embodiments.

Stabilized Compositions of Immiscible Olefin and Methods for Making theSame

Provided herein are microbial olefin compositions and methods forstabilizing and hydrogenating the same. The microbial olefins can bemade using any technique deemed suitable by one of skill in the art.Useful exemplary microbial methods for making olefinic isoprenoids aredescribed in U.S. Pat. No. 7,399,323; U.S. Patent Publication No.2008/0274523; and PCT Publication Nos. WO 2007/140339, WO 2008/140492,WO 2008/133658, and WO 2009/014636, all incorporated by reference intheir entireties. Useful exemplary microbial methods for makingfatty-acid derived olefins are described in U.S. Patent Publication No.2009/0047721; and PCT Publication Nos. WO 2008/113041 and WO2008/151149, all incorporated by reference in their entireties.

In one aspect provided herein is a method of stabilizing amicrobial-derived olefin. In one aspect a method of stabilizing amicrobial-derived olefin comprises adding a phenolic antioxidant to themicrobial-derived composition.

In certain embodiments, the method comprises:

-   -   a) separating immiscible olefin from a mixture comprising an        aqueous solution, microbial cells and immiscible olefin thereby        forming a crude olefin composition; and    -   b) adding a phenolic antioxidant to the crude olefin composition        to form a stabilized microbial-derived olefin composition.

In certain embodiments, the method further comprises purifying theolefin composition, before and/or after step b) to form a purifiedolefin composition.

In certain embodiments, the method comprises:

-   -   a) separating immiscible olefin from a mixture comprising an        aqueous solution, microbial cells and immiscible olefin thereby        forming a crude olefin composition;    -   b) purifying the crude olefin composition thereby forming a        purified olefin composition; and    -   c) adding a phenolic antioxidant to the purified olefin        composition to form a stabilized purified microbial-derived        olefin composition.

In certain embodiments, the method further comprises adding a phenolicantioxidant to the crude olefin composition before the purificationstep. In certain embodiments, the method further comprises adding aphenolic antioxidant to the olefin composition before and after thepurification step.

In certain embodiments, the method further comprises contacting thepurified olefin composition with hydrogen in the presence of ahydrogenation catalyst thereby forming a hydrogenated counterpart to theimmiscible olefin wherein at least one carbon-carbon double bond becomessaturated by the addition of hydrogen.

The olefin is derived from microbial cells. In certain embodiments, themicrobial cells are bacteria. In certain embodiments, the microbialcells belong to the genera Escherichia, Bacillus, Lactobacillus. Incertain embodiments, the microbial cells are E. coli. In furtherembodiments, the microbial cells are fungi. In still furtherembodiments, the microbial cells are yeast. In still furtherembodiments, the microbial cells are Kluyveromyces, Pichia,Saccharomyces, or Yarrowia. In additional embodiments, the microbialcells are S. cerevisiae. In certain embodiments, the microbial cells arealgae. In certain embodiments, the microbial cells are Chlorellaminutissima, Chlorella emersonii, Chloerella sorkiniana, Chlorellaellipsoidea, Chlorella sp., or Chlorella protothecoides.

In certain embodiments, the immiscible olefin is a hydrocarbon. Incertain embodiments, the immiscible olefin is a fatty acid or a fattyacid-derivative. In further embodiments, the immiscible olefin is anisoprenoid. In still further embodiments, the immiscible olefin is aC₅-C₂₀ isoprenoid. In certain embodiments, the immiscible olefin is aC₁₀-C₁₅ isoprenoid. In additional embodiments, the immiscible olefin isselected from careen, geraniol, linalool, limonene, myrcene, ocimene,pinene, sabinene, terpinene, terpinolene, amorphadiene, farnesene,farnesol, nerolidol, valencene, and geranylgeraniol. In furtheradditional embodiments, the immiscible olefin is myrcene, α-ocimene,β-ocimene, α-pinene, β-pinene, amorphadiene, α-farnesene or β-farnesene.In certain embodiments, the immiscible olefin is α-farnesene,β-farnesene, or a mixture thereof.

In certain embodiments, the purification step comprises fractionaldistillation. In certain embodiments, the purification step comprisesflash distillation (which is also known as flash or partialevaporation). In certain embodiments, the purification step comprisesadsorption. In certain embodiments, the purification step comprisessilica gel filtration. In certain embodiments, the purification stepcomprises alumina treatment. In additional embodiments, the purificationstep comprises liquid chromatography. In further embodiments, thepurification step comprises solvent extraction.

In certain embodiments, the impurities removed in the purification stepinclude, for example, cold insolubles, such as mono-, di-, andtriglycerides. When the host cells are yeast, the cold insolublesfurther includes ergosterol and squalene. In certain embodiments, theimpurities removed in the purification step include, for example,chemicals added in upstream processing, such as antifoams, deemulsifiersand other chemicals. When the host cells are yeast, the cold insolublesfurther includes ergosterol and squalene.

In certain embodiments, the phenolic antioxidant is a polyphenol. Incertain embodiments, the phenolic antioxidant is resveratrol. In certainembodiments, the phenolic antioxidant is a monophenol. In certainembodiments, the phenolic antioxidant is selected from:3-tert-butyl-4-hydroxyanisole; 2-tert-butyl-4-hydroxyanisole;2,4-dimethyl-6-tert-butylphenol; and 2,6-di-tert-butyl-4-methylphenol.In certain embodiments, the phenolic antioxidant is a catechol. Infurther embodiments, the phenolic antioxidant is 4-tert-butylcatechol.

In certain embodiments, the phenolic antioxidant is present in an amountthat is at least about 0.0001% by weight of the composition. In certainembodiments, the phenolic antioxidant is present in an amount that isbetween about 0.0001% and about 0.5% by weight of the composition. Incertain embodiments, the phenolic antioxidant is present in an amountthat is between about 0.0001% and about 0.01% by weight of thecomposition. In certain embodiments, the phenolic antioxidant is presentin an amount that is between about 0.0005 to 0.01%, 0.001 to 0.01%, or0.005 to 0.01% by weight of the composition. In certain embodiments, thephenolic antioxidant is present in an amount that is at least about0.005% by weight of the composition. In certain embodiments, thephenolic antioxidant is present in an amount that is between about0.005% and about 0.5% by weight of the composition. In furtherembodiments, the phenolic antioxidant is present in an amount that is atleast about 0.01% by weight of the composition. In additionalembodiments, the phenolic antioxidant is present in an amount that isbetween about 0.05% and about 0.3% by weight of the composition. Incertain embodiments, the phenolic antioxidant is present in an amountthat is at least about 0.0001%, 0.0005%, 0.001%, 0.005%, 0.01%, 0.05%.0.1% or 0.5%. In certain embodiments, the phenolic antioxidant ispresent in an amount that is greater than about 0.5% by weight of thecomposition.

In another aspect, a stabilized microbial olefin composition isprovided. The composition comprises:

a) an immiscible olefin wherein the immiscible olefin is present in anamount that is equal to or greater than about 93% by weight of thecomposition; and

b) a phenolic antioxidant wherein the phenolic antioxidant is present inan amount that is at least about 0.001% by weight of the composition.

In certain embodiments, the phenolic antioxidant is present in an amountthat is at least about 0.0001% by weight of the composition. In certainembodiments, the phenolic antioxidant is present in an amount that isbetween about 0.0001% and about 0.5% by weight of the composition. Incertain embodiments, the phenolic antioxidant is present in an amountthat is between about 0.0001% and about 0.01% by weight of thecomposition. In certain embodiments, the phenolic antioxidant is presentin an amount that is between about 0.0005 to 0.01%, 0.001 to 0.01%, or0.005 to 0.01% by weight of the composition. In certain embodiments, thephenolic antioxidant is present in an amount that is at least about0.005% by weight of the composition. In certain embodiments, thephenolic antioxidant is present in an amount that is between about0.005% and about 0.5% by weight of the composition. In furtherembodiments, the phenolic antioxidant is present in an amount that is atleast about 0.01% by weight of the composition. In additionalembodiments, the phenolic antioxidant is present in an amount that isbetween about 0.05% and about 0.3% by weight of the composition. Incertain embodiments, the phenolic antioxidant is present in an amountthat is at least about 0.0001%, 0.0005%, 0.001%, 0.005%, 0.01%, 0.05%.0.1% or 0.5%. In certain embodiments, the phenolic antioxidant ispresent in an amount that is greater than about 0.5% by weight of thecomposition.

In certain embodiments, the immiscible olefin in the composition ispresent in an amount that is at least about 93%, 94%, 95%, 96%, 97% orgreater by weight of the composition.

In certain embodiments, the immiscible olefin in the compositioncomprises farnesene in an amount that is at least about 50%, 60%, 70%,80%, 90% 93%, 95%, 97%, 99% or greater by weight of the composition.

Comparison of Chemically Synthesized and Microbial-Derived Olefins

A composition of microbial-derived olefin and a composition of itschemically synthesized counterpart can have different properties due tothe different impurities contained therein. In some cases, thesedifferences are immaterial to the desired end use. But, in certainsituations, these differences can have a material impact. The methodsand compositions provided herein relate to one of these situations. Asit will be described more fully below, the methods and compositions cansignificantly decrease the hydrogenation reaction time of amicrobial-derived olefin. The improvements from using the methods andprocesses can result in cost savings due to shorter hydrogenation times,milder reaction conditions, and longer catalyst lifetimes. Although thefollowing focuses on the hydrogenation of farnesene for the purposes ofillustration, similar results are obtained with other microbial-derivedimmiscible olefins.

Chemically synthesized β-farnesene was obtained from Bedoukian Research.Trans β-farnesene composition was obtained which was determined to beabout 90% pure by GCMS. When this sample was hydrogenated under fairlymild hydrogenation conditions (for example, 5% Pd/C at 60 psia at 100°C.), the hydrogenation initially proceeded at a rapid rate and then therate decreased over time as seen in FIG. 1. Several studies wereconducted to determine the cause of drop in the hydrogenation rate,including studies focused on the impurities from the chemical synthesisof farnesene. Subsequently, it was finally discovered that the decreasein hydrogenation rates was due to the presence of α-tocopherol, anantioxidant added by Bedoukian Research. The amount of α-tocopherol inthe commercial sample was about 0.1%.

FIG. 1 shows the plot of the rate of hydrogenation versus the hydrogenequivalents during a hydrogenation reaction of the Bedoukian 90% puretrans β-farnesene. However, when α-tocopherol is removed, for example bysilica gel filtration, then the sample hydrogenated readily. A highlypure 98% β-farnesene composition as well a mixture of a mixture ofα-farnesene and β-farnesene behaved similarly. In other words, ifα-tocopherol was present, the hydrogenation reaction (regardless of thepurity level of the farnesene sample) was impaired but if removed, thereaction proceeded readily under mild hydrogenation conditions. Becausethere were no significant differences between the hydrogenation behaviorof a 98% β-farnesene composition versus the 90% composition or theisomeric mixture, in the discussion below the hydrogenation reaction ofthe commercially synthesized composition is with the 90% transβ-farnesene sample unless otherwise noted. Similarly, all samples ofcommercially-obtained farnesene were treated to remove α-tocopherolprior to hydrogenation unless otherwise noted.

Because a potential stability issue was created from the removal ofα-tocopherol from commercially-obtained farnesene, the stability of atocopherol-free farnesene was investigated. As shown by FIG. 2, atocopherol-free farnesene was found to be stable at 20° C. for at least10 days. While the hydrogenation time was slightly higher (14.9 minutesper hydrogen equivalent), it was nevertheless comparable to thedifferent lots of farnesene in which the α-tocopherol was removed justprior to hydrogenation (9.3 minutes per hydrogen equivalent and 12.1minutes per hydrogen equivalent in two lots providing an average valueof 10.7±1.9 minutes per hydrogen equivalent). The hydrogenationconditions were 5% Pd/C at 60 psia at 100° C.

With these series of experiments, a baseline for comparison(hydrogenation of commercially available farnesene with α-tocopherolremoved prior to hydrogenation) was obtained. Although α-tocopherolcould be removed up to ten days prior to hydrogenation, where possible,it was removed just prior to hydrogenation.

With the baseline established, microbial-derived β-farnesene (95% pureby GCMS) was hydrogenated and compared with its chemically synthesizedcounterpart. The results are shown in FIGS. 3A and 3B. As it can be seenin FIGS. 3A and 3B, the microbial-derived farnesene contained one ormore inhibitors that impeded the progress of the hydrogenation reaction.

While efforts were made to identify the source of this inhibition inmicrobial-derived farnesene, a curious discovery was made. Crudemicrobial farnesene was found to be significantly more stable than itspurified counterpart. This fact is graphically illustrated in FIG. 4. Inthis series of experiments, microbial-farnesene was treated in differentways and stored for up to 60 days at 4° C. FIG. 4 is a plot showing thehydrogenation times under mild hydrogenation conditions (5% Pd/C at 60psia at 100° C.) for the various microbial farnesene as a function ofstorage time. Various microbial farnesene compositions used in thisstudy were obtained as described below.

Microbial cells that were genetically modified to make farnesene weregrown in culture medium, as described for example, by U.S. Pat. No.7,399,323 and PCT Publication No. WO 2007/139924. The cells wereseparated from the culture medium and the resulting broth wascentrifuged to purify immiscible organic layer from the aqueous medium.The resulting organic layer is the crude olefin composition wherein theimmiscible olefin is present in the composition in an amount greaterthan about 50% by weight but is less than about 92% by weight. The crudeolefin composition includes components which can precipitate fromsolution at cold temperatures (e.g. 4° C.). These precipitates whichwere termed “cold insolubles” include various glycerides such as mono-,di-, and triglycerides. When the immiscible olefin is produced in yeast,the cold insolubles also include ergosterol and squalene.

In certain embodiments, the crude olefin composition is a crudeβ-farnesene composition. In one aspect, removing the cells andseparating the immiscible layer from the aqueous broth, yields a crudeβ-farnesene composition of about 90% purity by GCMS.

The crude olefin composition can be further purified to a compositioncomprising an immiscible olefin wherein the olefin is present in thecomposition in an amount equal to or greater than about 93% by weight.In certain embodiments, the olefin is present in an amount equal to orgreater than about 95% by weight. Any purification method deemedsuitable by one of skilled in the art can be used. In certainembodiments, the sample is further purified by distillation. In certainembodiments, the sample is further purified by flash distillation. Incertain embodiments, distillation, including flash distillation iseffective at removing the cold insolubles.

In certain embodiments, the sample is further purified by liquidchromatography. In further embodiments, the sample is further purifiedby silica filtration, alumina filtration or clay filtration. In oneembodiment, the crude farnesene composition is further purified bysilica filtration and the resulting purified farnesene composition isgreater than 97% pure by GCMS.

As shown by FIG. 4, the crude farnesene composition is fairly stable asjudged by hydrogenation times which stay relatively constant over time.In contrast, the hydrogenation times for the purified farnesenecomposition increases over time. However, the hydrogenation time of arecently purified farnesene composition (time 0) is similar to that ofthe chemically synthesized counterpart in which the α-tocopherol isremoved.

The purified farnesene samples were further analyzed. In certainembodiments, these samples comprised farnesene in an amount that isequal to or greater than about 93% by weight based on GCMS. In certainembodiments, farnesene is present in an amount that is equal to orgreater than about 95% by weight or, in certain embodiments equal to orgreater than about 97% by weight. These purified farnesene samplesfurther comprised the following compounds which were all in an amountthat is at least about 0.05% by weight by GCMS: zingiberene (also knownas ginger oil) which can be present in an amount that is equal to orgreater than about 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, or 0.7%;bisabolene which can be present in an amount that is equal to or greaterthan about 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, or 0.7%;10,11-dihydro-10,11-epoxyfarnesene which can be present in an amountthat is equal to or greater than about 0.1%, 0.2%, 0.3%, 0.4%, 0.5%,0.6%, or 0.7%; and farnesol which can be present in an amount that isequal to or greater than about 0.1%, 0.25%, 0.5%, 0.75%, 1%, 1.5%, or2%.

Each of these components was added to a commercially obtained farnesenewith α-tocopherol removed to assess impact on hydrogenation times. Thehydrocarbons such as zingiberene and bisabolene had no effect onhydrogenation. Farnesol and the farnesene epoxide impeded hydrogenationonly slightly at the observed concentrations (1.3 to 2 times) and thuscould not account for the dramatic increases in hydrogenation times thatwere seen for purified farnesene compositions. Moreover, all of thesecomponents were also observed in the crude farnesene composition.

As shown by FIG. 5, the degradation in farnesene was correlated directlywith peroxide concentrations which increased over time in the purifiedsamples. Farnesene can be stabilized against peroxide formation byvarious antioxidants such as α-tocopherol. However, as describedpreviously, some of the most commonly used antioxidants such asα-tocopherol have been found to inhibit hydrogenation.

In the methods and compositions provided herein, phenolic antioxidantswere found to stabilize immiscible olefins without impeding anysubsequent hydrogenation. Illustrative examples of phenolic antioxidantsinclude polyphenols such as resveratrol; monophenols such as3-tert-butyl-4-hydroxyanisole; 2-tert-butyl-4-hydroxyanisole;2,4-dimethyl-6-tert-butylphenol; and 2,6-di-tert-butyl-4-methylphenol;and catechols such as 4-tert-butylcatechol. In certain embodiments, theaddition of up to 3 weight % of a phenolic antioxidant were shown not toaffect hydrogenation rates or times.

As shown in FIG. 5, the hydrogenation times of purified farnesenecomposition stabilized with 100 ppm of a phenolic antioxidant (100 ppmof TBC is 0.01% by weight) was comparable to that seen for thechemically synthesized counterpart in which the α-tocopherol is removed.Curiously, phenolic antioxidants such as TBC did not further improve thehydrogenation rate of a crude olefin composition. In certainembodiments, as shown by FIG. 4, the crude olefin composition appears toperform slightly better in the absence of a phenolic antioxidant thanwith it.

Hydrogenation

In another aspect, hydrogenation methods for microbial-derived olefinsare provided. Any known hydrogenation method can be used to hydrogenatemicrobial-derived olefins so long as the purified olefin compositioncomprises a phenolic antioxidant.

In one embodiment, a method provided herein comprises:

a) obtaining an immiscible olefin; and

b) reacting the immiscible olefin with hydrogen in the presence of ahydrogenation catalyst such that hydrogen saturates at least one doublebond in the immiscible olefin and wherein the hydrogenation reactionoccurs at a temperature that is greater than about 100° C.

In certain embodiments, the immiscible olefin is part of a crude olefincomposition. In certain embodiments, the immiscible olefin is part of apurified olefin composition. In certain embodiments, the immiscibleolefin is part of a stabilized purified olefin composition.

In certain embodiments, the hydrogenation reaction occurs at atemperature equal to or greater than room temperature. In certainembodiments, the hydrogenation reaction occurs at a temperature equal toor greater than 20° C., 30° C., 40° C., 50° C., 60° C., 70° C., 80° C.,90° C., 100° C., 110° C., 120° C., 130° C., 140° C., 150° C., 160° C.,170° C., 180° C., 190° C., or 200° C. In certain embodiments,hydrogenation can occur at temperatures below 100° C. when hydrogenatingan immiscible olefin. In certain embodiments, catalyst life issignificantly extended if hydrogenation of an immiscible olefin isconducted above 100° C. In certain embodiments, the hydrogenationreaction occurs at a temperature equal to or greater than about 110° C.,120° C., 130° C., 140° C., 150° C., 160° C., 170° C., 180° C., 190° C.,or 200° C. In certain embodiments, the hydrogenation reaction occurs ata temperature between about 110° C. and about 400° C. In certainembodiments, cracking side reactions become significant if thehydrogenation occurs at a temperature greater than about 400° C. Incertain embodiments, the hydrogenation reaction occurs at a temperaturebetween about 110° C. and about 350° C. In certain embodiments, thehydrogenation reaction occurs at a temperature between about 110° C. andabout 300° C. In certain embodiments such as when hydroprocessingcatalysts are used, the hydrogenation reaction occurs at a temperaturebetween about 170° C. and about 350° C. In certain embodiments, thehydrogenation reaction occurs at a temperature between about 170° C. andabout 240° C.

The benefits of performing the hydrogenation of microbial-derivedolefins at temperature above 100° C. are shown in FIG. 7. To test forcatalyst fouling, hydrogenation reactions were conducted at high processLHSV (Liquid Hourly Space Velocity) (process LHSV=12). Variouscompositions of 5% farnesene and 95% decane were hydrogenated at apressure of 500 psig using 20% Ni/Al₂O₃ catalyst diluted 4× with glassbeads. In the first part of the plot, the farnesene in the farnesenecomposition is a purified microbial-derived farnesene and thehydrogenation reaction occurs at 100° C. As can be seen, the catalystcan deactivate rapidly over one day and continues to deactivate overthree days. However, spent catalyst can be recovered by increasingtemperature to greater than 100° C. As shown by the second part of theplot, the hydrogen uptake was recovered almost fully by increasingtemperature to greater than 100° C. (in this case 150° C.). The thirdpart of the plot demonstrates that chemically-derived farnesene can behydrogenated at 100° C. with little or no catalyst deactivation.

In certain embodiments, the hydrogenation reaction occurs in a slurryreactor. In certain embodiments, the hydrogenation reaction occurs in afixed bed reactor. In certain embodiments, the hydrogenation reactionoccurs in a fluidized bed reactor. In certain embodiments, thehydrogenation reaction occurs in a batch reactor. In furtherembodiments, the hydrogenation reaction occurs in a continuous flowreactor.

Hydrogen for use in the process can be obtained from any source deemedsuitable by one of skill in the art. Exemplary sources include LindeGroup, Air Products Praxair, and Air Liquid. Alternatively, hydrogen canbe generated by steam methane reforming where pressurized natural gasand deionized water are fed to a steam methane reformer and converted tohydrogen via the following overall reaction:CH₄(gas)+2H₂O(gas)→CO₂(gas)+4H₂(gas).

Carbon monoxide, carbon dioxide, water, and other gaseous contaminantscan be separated from hydrogen via pressure-swing adsorption. Theresulting hydrogen purity is typically 99% or greater. Another methodfor in situ hydrogen generation is by electrolysis. De-mineralized wateris fed to an electrolysis unit and is converted to hydrogen via thefollowing reaction:2H₂O(liquid)→O₂(gas)+2H₂(gas).

In certain embodiments, the hydrogen composition used in the process isat least about 85%, 90%, 95%, 97%, 99% 99.5% or 99.99% pure. In certainembodiments, residual CO_(X) is ≦50 ppm. In certain embodiments, thehydrogen composition includes no measurable H₂S.

Any hydrogenation catalyst can be used in the practice of a processprovided herein. Exemplary catalysts are described, for example, in U.S.Pat. Nos. 6,403,844; 5,379,767; 5,151,172; 4,968,612; and 3,702,348. Incertain embodiments, the catalyst is selected from Ni, Pd, Ru, Pt, Rh,Ir, Cu and Fe; alloys of the platinum group catalysts with promoters orstabilizers such as Mo, Co, Mg, and Zn; Raney-type porous catalysts,such as Ni/Al, Co/Al, and Cu/Al; and hydroprocessing catalysts, such asNiMoS and CoMoS.

The catalyst can be provided in any suitable form, with a minimumdimension of, for example, at least 1 mm. Specific particle dimensionscan be selected based upon reaction conditions and the type of catalystbed being used. The catalyst can include any shape providing sufficientsurface area, including but not limited to, cylinders, tablets,granules, spheres, lobed cylinders, or combinations thereof. Thecatalyst can also contain holes or passages. The particles can be formedby methods known in the art, such as, for example, extrusion ortabletting, or the like.

Although many catalysts can be used, an important factor for large scalehydrogenation is catalyst cost. In these situations, a catalyst isselected by balancing reactivity with costs. Of the platinum groupmetals, the order of reactivity was found to be Pd>Rh>Pt>>Ru.Fortuitously, the palladium catalysts also happen to be the leastexpensive of the highly active platinum group metals. For example,recent prices were: Pd=$200/oz; Rh=$1000/oz; Pt=$970/oz; Ru=$80/oz.

Although good results have been achieved with Pd catalysts, particularlythe 5% Pd/C catalyst, Pd catalyst costs still can be a significantexpense on a commercial scale. As a result, various lower cost catalystswere screened. Various Pd and Ni catalysts as well as NiMo and CoMohydroprocessing catalysts can be used. Based on these screens, the mostcost effective catalysts were selected that performed well under lowtemperature and low catalyst loading conditions. An illustrative panelof catalysts and results are shown by FIG. 6 which shows thehydrogenation rate of limonene at 0.5, 1, 2, and 3 equivalents ofhydrogen at 100° C. and 50 mg of catalyst loading.

Of these, Ni-based catalysts were identified as a very cost effectiveoption while being capable of operating at extremely high LHSVs (LiquidHourly Space Velocity). A recent price for Ni which is typically pricedby the pound was $0.33/oz. Exemplary Ni catalysts include “Raney Ni”,“sponge Ni”, and “skeletal Ni”. In certain embodiments, the catalyst isselected from Ni and Pd catalyst.

When the catalyst is used with a fixed bed support, any suitablematerial with high mechanical strength, high thermal stability, and lowsurface tension with supported metals can be used. In certainembodiments, useful support materials include, for example, silica,titania, zirconia, alumina, keiselguhr, magnesia, calcium aluminatecements, other inorganic carriers, carbon, and other known materials ormodified versions of these supports such as base-treated versions, orversions with stabilizing additives such as MgO or oxides from theLanthanide series. A catalyst support can be in the form of a pellet orextrudate with size dimensions on the order of 0.1-5 mm, 0.5-5 mm, 1-5mm, 1-4, or 1-3 mm.

Exemplary Ni catalysts with a fixed bed support include Al₂O₃ supportedNi, Si-supported Ni, and sponge-type Ni. The activity of these catalystscan be optionally further modulated by the addition of a promoter orstabilizer such as Mo. Preferred Ni-based catalysts include Al₂O₃supported catalysts such as 20%, 12%, or 8% Ni/Al₂O₃. These Ni-basedcatalysts also have a price advantage: although both 20% Ni/Al₂O₃ and0.3% Pd/Al₂O₃ catalysts can provide similar hydrogenation performance,the cost per unit reactor volume of the 20% Ni/Al₂O₃ catalyst isapproximately 40% of the cost of the 0.3% Pd/Al₂O₃ catalyst. In certainembodiments, the catalyst for use in a process provided herein isselected from 20% Ni/Al₂O₃ and 0.3% Pd/Al₂O₃.

When the hydrogenation reaction occurs in a fixed bed reactor, anysuitable fixed bed reactor can be used. Exemplary reactors include aone-stage fixed bed reactor, a two-stage fixed bed reactor, and amulti-stage fixed bed reactor.

Many configurations of a fixed bed reactor are known in the art.Exemplary configurations include: i) cocurrent gas-liquid downflow wherereactant liquid and hydrogen gas is fed to a fixed bed reactorcocurrently to the top, described, for instance, by R. Gupta, in“Cocurrent Gas-Liquid Downflow in Packed Beds”, Chapter 19, of theHandbook of Fluids in Motion (1983); ii) cocurrent upflow where reactantliquid and hydrogen gas are fed to a fixed-bed reactor cocurrently tothe bottom, and iii) countercurrent operations where reactant liquid andhydrogen gas are fed to a fixed-bed reactor countercurrently with liquidfed to the top trickling through rising hydrogen that is fed to thebottom, as described by P. Trambouze, in “Countercurrent Two-Phase FlowFixed Bed Catalytic Reactions,” Chemical Engineering Science, Vol 45,No. 8, pp 2269-2275 (1990).

The hydrogenation reactions described herein can be extremelyexothermic, particularly when the immiscible olefin has multiple doublebonds. As a consequence, strategies for removing potentially largeamounts of heat need to be in place. For example, the hydrogenation offarnesene would result in a temperature rise of about 1000° C. ifperformed adiabatically. Thus, if hydrogenation were to occur in aslurry reactor or an ebullated bed reactor, heat would need to becontinually removed. Because these systems are well-mixed, the heat ofreaction can be transferred to internal cooling coils or externalcooling jackets efficiently. Because of the complexities in havingmechanical agitation, the limitation in size imposed thereof, as well asthe requirement for catalyst filtration, mechanically-agitated slurryreactors may be more useful for smaller scale reactions.

In certain embodiments, fixed bed reactors are used for large scalehydrogenations. These reactors have the advantage of simplicity becausethey require no mechanical agitation or catalyst filtration.

Various strategies can be used to remove heat from fixed bed reactors.In certain embodiments, a plurality of small diameter reaction tubes canbe used. The small diameter can allow heat of reaction to be conductedradially out of the tubes effectively due to the short distance the heatneeds to conduct over.

In certain embodiments, a chilled product stream can be recycled fromthe reactor effluent to act as a diluent. In one embodiment, the diluentis the intended product, a saturated immiscible olefin. The coldeffluent can act as a heat sink for the heat of reaction so that thetemperature rise for a fixed rate of reactant addition decreases as moreproduct liquid is mixed into the feed. This strategy is particularlyeffective when the hydrogenation of the reactant exhibits zero orderkinetics. For example, FIG. 8 is a plot of the hydrogen uptake versusvarious dilution of farnesene. A calculated curve for a first orderreaction based on hydrogen uptake of 20% farnescene concentration isshown along with the observed response for farnesene. As it can be seen,because a reactant like farnesene exhibits zero order kinetics, dilutesolutions (less than <20%, <15%, <10%, and even <5%) can be efficientlyhydrogenated.

In other embodiments, the diluent is a compound or composition that isinert under the employed hydrogenation conditions. Illustrative examplesinclude saturated hydrocarbons that are not the hydrogenated immiscibleolefin. For example, diluents can be n-pentane, n-hexane, n-heptane,n-octane, n-decane, and the like.

In still other embodiments, the diluent is a hydrogenated immiscibleolefin. In certain embodiments, the diluent is a saturated immiscibleolefin.

In another aspect, a hydrogenation method using a fixed bed reactor isprovided. The method comprises:

-   -   a) providing a feed stream to the inlet of a fixed bed reactor        wherein the feed stream comprises an immiscible olefin and a        diluent composition;    -   b) contacting the feed stream with hydrogen in the presence of a        hydrogenation catalyst at a temperature greater than room        temperature thereby producing an effluent;    -   c) separating the effluent which comprises a hydrogenated        immiscible olefin into a product stream comprising a        hydrogenated immiscible olefin and a recycle stream comprising a        hydrogenated immiscible olefin;    -   d) adding the recycle stream as part of the diluent composition        to a stream comprising the immiscible olefin to form a feed        stream comprising recycled hydrogenated immiscible olefin;    -   e) providing the feed stream comprising recycled hydrogenated        immiscible olefin to the inlet of the fixed bed reactor; and    -   f) repeating steps b)-e) at least once.

In another aspect, a hydrogenation method comprises:

-   -   a) providing a feed stream to the inlet of a fixed bed reactor        wherein the feed stream comprises an immiscible olefin and a        diluent composition;    -   b) contacting the feed stream with hydrogen in the presence of a        hydrogenation catalyst at a temperature greater than about        100° C. thereby producing an effluent;    -   c) separating the effluent which comprises a hydrogenated        immiscible olefin into a product stream comprising a        hydrogenated immiscible olefin and a recycle stream comprising a        hydrogenated immiscible olefin;    -   d) adding the recycle stream as part of the diluent composition        to a stream comprising the immiscible olefin to form a feed        stream comprising recycled hydrogenated immiscible olefin;    -   e) providing the feed stream comprising recycled hydrogenated        immiscible olefin to the inlet of the fixed bed reactor; and    -   f) repeating steps b)-e) at least once.

In certain embodiments, the immiscible olefin is part of a crude olefincomposition. In certain embodiments, the immiscible olefin is part of apurified olefin composition.

In certain embodiments, the diluent composition comprises a hydrogenatedimmiscible olefin. In certain embodiments, the diluent compositioncomprises a saturated immiscible olefin. In certain embodiments, thediluent composition comprises recycled hydrogenated immiscible olefin incombination with one or more other diluents. In further embodiments, thediluent composition comprises recycled saturated immiscible olefin incombination with one or more other diluents.

In certain embodiments, the feed stream comprises about 1%, 5%, 10%,25%, 50%, 75%, 90%, 95%, 99% or less diluent based on total weight ofthe immiscible olefin. In certain embodiments, the feed stream comprisesabout 50 to 95%, 30 to 95%, 20 to 95%, or 5 to 99% diluent based ontotal weight of the immiscible olefin. In certain embodiments, the feedstream comprises about 99%, 95%, 90%, 85%, 75%, 65%, 55%, 45%, 35%, 25%,15%, 5% or 1% diluent based on total weight of the immiscible olefin.

In certain embodiments, the feed stream comprises about 1%, 5%, 10%,25%, 50%, 75%, 90%, 95%, 99% or less hydrogenated immiscible olefinbased on total weight of the diluent. In further embodiments, the feedstream comprises about 50 to 95%, 50 to 90%, 30 to 95%, 20 to 95%, 5 to97% or 60 to 85% hydrogenated immiscible olefin based on total weight ofthe diluent. In certain embodiments, the feed stream comprises about99%, 95%, 90%, 85%, 75%, 65%, 55%, 45%, 35%, 25%, 15%, 5% or 1%hydrogenated immiscible olefin based on total weight of the diluent. Inadditional embodiments, the feed stream comprises about 50 to 95%, 50 to90%, 30 to 95%, 20 to 95%, 5 to 97% or 60 to 85% saturated immiscibleolefin based on total weight of the diluent. In further embodiments, thefeed stream comprises about 99%, 95%, 90%, 85%, 75%, 65%, 55%, 45%, 35%,25%, 15%, 5% or 1% saturated immiscible olefin based on total weight ofthe diluent.

In certain embodiments, the feed stream comprises about 5%, 10%, 25%,50%, or 75% or less immiscible olefin based on total weight of the feedstream. In further embodiments, the feed stream comprises about 1 to50%, 5 to 50%, 5 to 25%, 10 to 50%, 10 to 40% or 10 to 25% immiscibleolefin based on total weight of the feed stream. In certain embodiments,the feed stream comprises about 50%, 40%, 30%, 25%, 20%, 10%, 5% or 1%immiscible olefin based on total weight of the feed stream.

In certain embodiments, the catalyst is a Pd catalyst. In certainembodiments the catalyst is a Ni catalyst. In certain embodiments, thecatalyst is Ni/Al₂O₃.

In certain embodiments, the temperature difference between the inlet andthe outlet of the fixed bed reactor is not more than 200° C. In certainembodiments, the temperature difference between the inlet and the outletof the fixed bed reactor is not more than 100° C. In certainembodiments, the temperature difference between the inlet and the outletof the fixed bed reactor is not more than 50° C.

FIG. 9 is a schematic of an exemplary fixed bed hydrogenation system.The system comprises a primary reactor 3 (with primary catalyst 4).Optionally, the system comprises a secondary reactor 6 (with secondarycatalyst 7). The primary catalyst and the secondary catalyst may beidentical or they may be different. If the system comprises only aprimary reactor, this is a one-stage reactor where hydrogenation occursin the primary reactor and the hydrogenated immiscible olefin isseparated into two fractions: a recycling fraction and a productfraction. The recycling fraction is then recirculated as a diluent forthe immiscible olefin feed. The hydrogenated immiscible olefin that isthe product fraction can be used without further treatment.

If the system comprises both a primary and secondary reactor, this is atwo-stage reactor. As with the one-stage reactor, hydrogenation occursin the primary reactor and the hydrogenated immiscible olefin isseparated into two fractions: a recycling fraction and a productfraction. The recycling fraction is then recirculated as a diluent forthe immiscible olefin feed to the primary reactor. The hydrogenatedimmiscible olefin that is the product fraction can be furtherhydrogenated to remove any residual unsaturation.

In addition to the reactors 3 and 6 depicted in FIG. 9, the system cancomprise a feed holding tank 1, a liquid pump 2, a separator drum 5 toseparate gas from liquid, and hydrogen recycle compressor 21. The systemcan include one or more of the following: a filter for immiscible olefinfeed 8, a startup heater to heat the feed 9 to a desired temperature, aninterchanger 10 a and a cooler 10 b for the product exiting from theprimary reactor, a cooler 11 for the product exiting from the secondaryreactor, a cooler 12 for hydrogen exiting the separator drum, a tee orVenturi-type eductor 13 where the immiscible olefin feed is mixed withhydrogen, a primary reactor inlet 14, a primary reactor outlet 15, aknock-out pot 16 to separate gas and vapour, a secondary reactor inlet17, a secondary reactor outlet 18, a vent 19 to purge gases from thesystem and a liquid pump 20.

In some embodiments where a fixed bed reactor is used, the immiscibleolefin is mixed with a diluent. In certain embodiments, immiscibleolefin feed entering the reactor comprises between about 5% and 20%immiscible olefin by volume. In certain embodiments, immiscible olefinfeed entering the reactor is between about 5%, 10%, 15% and 20%immiscible olefin by volume.

In certain embodiments, the diluted immiscible olefin feed is mixed withhydrogen in a tee or Venturi-type eductor 13. In certain embodiments,about 1-1000%, 10-500 or 50-100% stoichiometric excess hydrogen, orabout 100-5000, 100-2000, 200-1000 or 200-400 standard cubic feet perbarrel of feed (scf/bbl) is used in the process. In certain embodiments,about 100% stoichiometric excess hydrogen, or about 200 standard cubicfeed per barrel of feed (scf/bbl) is used in the process.

In certain embodiments, the hydrogenation process is carried out atpressures between about 100 psig to about 700 psig. The pressuretypically is between 100 and 700 psig at reaction inlet 14 and between 5and 10000 psig at reaction outlet 15. In certain embodiments, pressureat reaction inlet 14 is about 400 psig, 450 psig, 500 psig, 530 psig or550 psig. In one embodiment, pressure at reaction inlet 14 is about 530psig. In one embodiment, pressure at reaction outlet 15 is about 400psig, 450 psig, 500 psig, or 550 psig. In one embodiment, pressure atreaction inlet 14 is about 530 psig and pressure at outlet 15 is about500 psig.

In certain embodiments, the temperature during the process depends uponthe operating pressures but typically a hydrogenation process is carriedout at temperature greater than 100° C. In certain embodiments, thetemperature is about 110 to 200° C. at the inlet 14 and between about150 to 350° C. at the outlet 15.

In certain embodiments, an axial temperature rise is specified based onthe difference between the reaction light-off temperature and thetemperature at which the catalyst begins to foul. In other embodiments,in the hydrogenation process is near, but above the temperature at whichthe hydrogenation of begins, i.e., light-off temperature, and below thetemperature at which catalyst fouling or lost product yield aresignificant. In certain embodiments, the axial temperature rise in theprocess is in the range of 10 to 300° C. In certain embodiments, theaxial temperature rise in the process is about 10, 20, 30, 40, 45, 50,55, 60, 65, 70, 80, 100, 150, 200 or 300° C. Exemplary hydrogenationreactions with axial temperature rise at about 200° C. are described inU.S. Pat. No. 3,796,764.

In certain embodiments, the temperature at the inlet 14 of the reactoris about 150° C., and the pressure is about 530 psig. In one embodiment,the multi-phase feed flow and hydrogen stream are forced down thereactor 3 by the dynamic pressure drop, and exits the reactor at about500 psig.

In certain embodiments, primary reactor 3 comprises a sacrificial layerof catalyst or an adsorbent at the head of the reactor, to accumulateany irreversibly binding catalyst poisons and prevent them fromaccumulating on the catalyst below. In certain embodiments, thesacrificial layer is composed of a support having a larger particlesize, larger pore dimensions, and/or lower metal loading than thecatalyst. In certain embodiments, larger particle and pore dimensions ofthe sacrificial layer support allow more material to accumulate on thesacrificial section before the pores and interstitial spaces becomeclogged, which results in large pressure drop necessary to drive flow.In further embodiments, a lower metal content of the sacrificial layercan reduce catalyst cost and can decrease hydrogenation rate at activesites, which can increase hydrogen availability at active sites and candecrease the potential for side reactions, including catalyst cokingreactions that may occur in the absence of hydrogen. In still furtherembodiments, one, two, three or multiple sacrificial layers are presentin the fixed bed. In additional embodiments, the sacrificial layer ofcatalyst comprises a topmost layer of a catalyst support material, suchas Al₂O₃, followed by a layer of a low loading of Ni on a suitablesupport, such as Al₂O₃, in order to prolong the life of the sacrificiallayers.

Primary reactor 3 can further comprise a primary catalyst 4. In oneembodiment, the primary catalyst is a Ni catalyst containing about 20%Ni supported on alumina extrudate, with an extrudate diameter of 1-5 mm.An example of a catalyst for use in the process is HTC NI 500 RP 1.2 mmavailable from Johnson-Matthey. In certain embodiments, the Ni loadingin the catalyst is about 10%, 7%, 5%, 3% or less. In one embodiment, theNi loading in the catalyst is about 5% or less. In certain embodiments,the loading of Ni is about 60% or greater to minimize reactor volumeand/or prolong catalyst life. In certain embodiments, the primarycatalyst comprises 0.3% Pd/Al₂O₃.

In certain embodiments, primary reactor 3 is sized with a reactor LHSV(Liquid Hourly Space Velocity) of 2, 5, 10, 15, 20 or 25, meaning thatthe ratio of the volumetric feed of liquid per hour to the volume of theprimary catalyst bed is 2, 5, 10, 15, 20 or 25. In certain embodiments,the primary reactor is sized with a reactor LHSV of 20. If theimmiscible olefin is diluted such that the feed is about 5% olefin and95% hydrogenated product, this is equivalent to a process LHSV of 1,meaning that the ratio of the volumetric feed of immiscible olefin perhour to the volume of the primary catalyst bed is 1. In certainembodiments, the process is operated at LHSV of 2 or higher.

In certain embodiments, the aspect ratio (ratio of reactorheight:diameter) for reactor 3 is between about 0.5 to 100, 0.5 to 50,0.5 to 30, 0.5 to 20, 1 to 15, 1 to 10, 1 to 7 or about 1 to 5. Incertain embodiments, the aspect ratio is between 1 and 5. In general,lower aspect ratios decrease the pressure drop across the reactor, andtherefore the electrical consumption of the recycle pump and recyclecompressor. Higher aspect ratios can result in greater turbulent mixingof the reacting fluids, which improves mass and heat transfer, which maymitigate the potential for catalyst fouling and hot spot formation.

In certain embodiments, the primary reactor contains a fluid distributorat the top of the reactor, for example, to evenly distribute themulti-phase reactant flow across the width of the reactor. In certainembodiment, one or more additional fluid distributors are positionedfurther into the reactor. In certain embodiments, one or more additionalfluid distributors are positioned such that the fluid in the reactor isre-distributed once every 30 feet of catalyst height.

In certain embodiments, product exiting at the bottom of the reactor iscooled by an interchanger 10 a and a cooler 10 b. In certainembodiments, the product exits at the bottom of the reactor at about195° C. and about 500 psig. The excess hydrogen (e.g., ˜100 scf H₂/bblliquid) can be disengaged from the liquid reactants in the gas/liquidseparator 5. Excess hydrogen can be pulled through a gas cooler 12 and aknock-out pot 16 by a recycle compressor 21. A purge stream can releasebetween ˜1% and ˜10% of the recycled hydrogen to vent 19. This can allowsmall amounts of gases generated during the reaction, such as methane,to exit the system. The recycled hydrogen can be mixed with make-uphydrogen downstream of the compressor 21, before mixing with theimmiscible olefin feed.

In certain embodiments, a fraction of the cooled liquid product fromprimary reactor 3 is recycled by a liquid pump 20 to the head of reactor3 as a recycle product fraction to dilute incoming, fresh immiscibleolefin feed. A remaining fraction of the liquid product can be divertedto a second reaction stage for polishing, which can reduce the residualunsaturation in the product fraction to the desired specification of thefinal hydrogenation product. A stoichiometric amount of hydrogen can beadded to the second stage.

The secondary reactor 6 contains a secondary catalyst 7. In certainembodiments, the secondary catalyst has a similar catalyst loading asthe primary catalyst 4, or it may be loaded with a higher-activitycatalyst, such as a high loading of supported Pd. In certainembodiments, the secondary reactor 6 comprises 5% Pd/Al₂O₃ catalyst. Incertain embodiments, the secondary reactor is sized with a reactor LHSVof 1, 2, 3, 4, 5 or 7. In certain embodiments, the secondary reactor issized so that its LHSV is 5.

In certain embodiments, the secondary reactor operates at about 300 to500 psig. In certain embodiments, the secondary reactor operates atabout 130-200° C. In certain embodiments, the secondary reactor operatesat about 500 psig and at about 150-190° C.

In another aspect, a hydrogenation method using existing hydroprocessingequipment is provided. Because hydroprocessing typically occurs in arefinery setting, they are able to handle high temperature reactions. Inthis method, hydrogenation of the immiscible olefin and hydroprocessingof the unfinished diesel occurs in the same reactor resulting in asaturated olefin and a finished diesel that has a reduced sulfur contentthat is 50 ppmw or less. The method comprises:

-   -   a) providing a feed stream to the inlet of a fixed bed reactor        wherein the feed stream comprises an immiscible olefin and a        diluent composition; and    -   b) contacting the feed stream with hydrogen in the presence of a        hydrogenation catalyst at a temperature greater than about        100° C. thereby producing an effluent,        wherein the diluent composition is an unfinished diesel that has        a sulfur content greater than 50 ppmw and the effluent comprises        saturated immiscible olefin and the effluent has a sulfur        content that is less than 50 ppmw.

In certain embodiments, the immiscible olefin is part of a crude olefincomposition. In certain embodiments, the immiscible olefin is part of apurified olefin composition.

In certain embodiments, the unfinished diesel has a sulfur content thatis greater than 100 ppmw, greater than 500 ppmw, greater than 1000 ppmw,greater than 5000 ppmw, or greater than 10,000 ppmw. In otherembodiments the unfinished diesel has a nitrogen content that is greaterthan 10 ppmw, greater than 50 ppmw, greater than 100 ppmw, greater than500 ppmw, greater than 1000 ppmw, greater than 5000 ppmw, or greaterthan 10,000 ppmw.

In certain embodiments, the effluent or the finished diesel has a sulfurcontent that is less than 30 ppmw. In other embodiments, the effluenthas a sulfur content that is less than 15 ppmw. In still otherembodiments, the effluent has a nitrogen content that is less than 1ppmw.

Alternatively, the unfinished diesel could be used as a diluent asdescribed above. In this method, hydrogenation of the immiscible olefinand hydroprocessing of the unfinished diesel occurs in the same reactorbut the effluent is recycled to control the temperature of the reaction.The method comprises:

-   -   a) providing a feed stream to the inlet of a fixed bed reactor        wherein the feed stream comprises an immiscible olefin and a        diluent composition wherein the diluent composition comprises        unfinished diesel that has a sulfur content that is greater than        50 ppmw such that the feed stream has a sulfur content that is        greater than 50 ppmw;    -   b) contacting the feed stream with hydrogen in the presence of a        hydrogenation catalyst at a temperature greater than about        100° C. thereby producing an effluent wherein the effluent        comprises saturated immiscible olefin and the effluent has a        sulfur content that is less than 50 ppmw;    -   c) diverting part of the effluent stream into a recycle stream        comprising a finished diesel that has a sulfur content that is        less than 50 ppmw;    -   d) adding the recycle stream as part of the diluent composition        to a stream comprising the immiscible olefin to form a feed        stream comprising immiscible olefin and the feed stream has a        sulfur content that is greater than 50 ppmw;    -   e) providing the feed stream to the inlet of the fixed bed        reactor; and    -   f) repeating steps b)-e) at least once.

In certain embodiments, the immiscible olefin is part of a crude olefincomposition. In certain embodiments, the immiscible olefin is part of apurified olefin composition.

In certain embodiments, the unfinished diesel has a sulfur content thatis greater than 100 ppmw, greater than 500 ppmw, greater than 1000 ppmw,greater than 5000 ppmw, or greater than 10,000 ppmw. In otherembodiments the unfinished diesel has a nitrogen content that is greaterthan 10 ppmw, greater than 50 ppmw, greater than 100 ppmw, greater than500 ppmw, greater than 1000 ppmw, greater than 5000 ppmw, or greaterthan 10,000 ppmw.

In certain embodiments, the effluent has a sulfur content that is lessthan 30 ppmw. In other embodiments, the effluent has a sulfur contentthat is less than 15 ppmw. In still other embodiments, the effluent hasa nitrogen content that is less than 1 ppmw.

In certain embodiments, the feed stream comprises about 1%, 5%, 10%,25%, 50%, 75%, 90%, 95%, 99% or less diluent based on total weight ofthe immiscible olefin. In certain embodiments, the feed stream comprisesabout 50 to 95%, 30 to 95%, 20 to 95%, or 5 to 99% diluent based ontotal weight of the immiscible olefin. In certain embodiments, the feedstream comprises about 99%, 95%, 90%, 85%, 75%, 65%, 55%, 45%, 35%, 25%,15%, 5% or 1% diluent based on total weight of the immiscible olefin.

In certain embodiments, the diluent composition comprises unfinisheddiesel that has a sulfur content that is greater than 50 ppmw and ahydrogenated immiscible olefin. In certain embodiments, the feed streamcomprises about 1%, 5%, 10%, 25%, 50%, 75%, 90%, 95%, 99% or lessunfinished diesel based on total weight of the diluent. In certainembodiments, the diluent composition comprises about 99%, 95%, 90%, 85%,75%, 65%, 55%, 45%, 35%, 25%, 15%, 5% or 1% unfinished diesel based ontotal weight of the diluent.

In certain embodiments, the feed stream comprises about 1%, 5%, 10%,25%, 50%, 75%, 90%, 95%, 99% or less hydrogenated immiscible olefinbased on total weight of the diluent. In further embodiments, the feedstream comprises about 50 to 95%, 50 to 90%, 30 to 95%, 20 to 95%, 5 to97% or 60 to 85% hydrogenated immiscible olefin based on total weight ofthe diluent. In certain embodiments, the feed stream comprises about99%, 95%, 90%, 85%, 75%, 65%, 55%, 45%, 35%, 25%, 15%, 5% or 1%hydrogenated immiscible olefin based on total weight of the diluent. Inadditional embodiments, the feed stream comprises about 50 to 95%, 50 to90%, 30 to 95%, 20 to 95%, 5 to 97% or 60 to 85% saturated immiscibleolefin based on total weight of the diluent. In further embodiments, thefeed stream comprises about 99%, 95%, 90%, 85%, 75%, 65%, 55%, 45%, 35%,25%, 15%, 5% or 1% saturated immiscible olefin based on total weight ofthe diluent.

In certain embodiments, the feed stream comprises about 5%, 10%, 25%,50%, or 75% or less immiscible olefin based on total weight of the feedstream. In further embodiments, the feed stream comprises about 1 to50%, 5 to 50%, 5 to 25%, 10 to 50%, 10 to 40% or 10 to 25% immiscibleolefin based on total weight of the feed stream. In certain embodiments,the feed stream comprises about 50%, 40%, 30%, 25%, 20%, 10%, 5% or 1%immiscible olefin based on total weight of the feed stream.

In certain embodiments, the catalyst is a hydroprocessing catalyst. Incertain embodiments the catalyst is a Ni catalyst. In certainembodiments, the catalyst is NiMo catalyst.

Farnesene

In another aspect, a purified farnesene composition is provided. Thecomposition comprises:

a microbial-derived mixture comprising farnesene in an amount that isequal to or greater than about 93% by weight and the following compoundseach of which is present in an amount that is equal to or greater thanabout 0.1% by weight: bisabolene, zingiberene, farnesol, and farneseneepoxide; and,

a phenolic antioxidant wherein the phenolic antioxidant is present anamount that is at least about 0.0001% by weight.

In another aspect, a purified farnesene composition is provided. Thecomposition comprises:

a microbial-derived mixture comprising farnesene in an amount that isequal to or greater than about 93% by weight and the following compoundseach of which is present in an amount that is equal to or greater thanabout 0.1% by weight: bisabolene, zingiberene, farnesol, and farneseneepoxide; and,

a phenolic antioxidant wherein the phenolic antioxidant is present anamount that is at least about 0.001% by weight.

In certain embodiments, the phenolic antioxidant is present in an amountthat is at least about 0.0005% by weight. In certain embodiments, thephenolic antioxidant is present in an amount that is at least about0.005% by weight. In certain embodiments, the phenolic antioxidant ispresent in an amount that is between about 0.005% and about 0.5% byweight. In further embodiments, the phenolic antioxidant is present inan amount that is at least about 0.01% by weight. In additionalembodiments, the phenolic antioxidant is present in an amount that isbetween about 0.05% and about 0.3% by weight. In certain embodiments,the phenolic antioxidant is present in an amount that is greater thanabout 0.5% by weight.

In certain embodiments, the microbial-derived mixture further comprisessqualene. The amount of squalene is generally less than about 0.5% basedon total weight of the microbial-derived farnesene. In certainembodiments, the amount of squalene is about 0.05% to 0.5% based ontotal weight of the microbial-derived farnesene. In further embodiments,the amount of squalene is about 0.05%, 0.08%, 0.09%, or 0.1% based ontotal weight of the microbial-derived farnesene.

In some cases, the microbial-derived mixture further comprises farnesenedimers, such 1,4 and 1,3 adducts of farnesene. The amount of dimers istypically less than about 0.5% based on total weight of themicrobial-derived farnesane. In certain embodiments, the amount offarnesene dimers is about 0.05%, 0.07%, 0.09%, 0.1%, 0.15%, 0.2%, 0.25%,0.3% or 0.5% based on total weight of the microbial-derived farnesene.In certain embodiments, the amount of farnesene dimers is about 0.2%based on total weight of the microbial-derived farnesene.

When the microbial-derived farnesene composition is hydrogenated,farnesene hydrogenates to farnesane. Both bisabolene and zingiberenehydrogenate to bisabolane. Farnesol becomes either farnesane (eliminatesthe hydroxyl group to form farnesene which then subsequentlyhydrogenates to become farnesane) or forms 2,6,10-trimethylundecane(plus methane and water). The latter reaction is depicted below:C₁₅H₂₅OH+5H₂→C₁₄H₃₀+CH₄+H₂O

Farnesene epoxide is hydrogenated to farnesol which is converted intofarnesane or 2,6,10-trimethylundecane as depicted above.

Thus in another aspect, a purified farnesane composition is provided.The composition comprises: farnesane in an amount that is equal to orgreater than about 93% by weight and bisabolane in an amount that isequal to or greater than about 0.1% by weight, wherein the wt. % isbased on the total weight of farnesane. In some embodiments, the amountof bisabolane is equal to or greater than about 0.2%, 0.3%, 0.4%, 0.5%,0.6%, 0.7%, 0.8%, 0.9% or 1.0% based on the total weight of farnesane.In other embodiments, the composition comprises: farnesane in an amountthat is equal to or greater than about 93% by weight; bisabolane in anamount that is equal to or greater than about 0.1% by weight; and2,6,10-trimethylundecane in an amount that is equal to or greater thanabout 0.1% by weight.

In cases where the microbial-derived farnesene mixture includessqualene, then the purified composition will further comprise squalane.The amount of squalane is generally less than about 0.5% based on totalweight of the farnesane. In certain embodiments, the amount of squalaneis about 0.05% to 0.5% based on total weight of the farnesane. Infurther embodiments, the amount of squalane is about 0.05%, 0.08%,0.09%, or 0.1% based on total weight of the farnesane.

In some cases where the microbial-derived farnesene mixture includesfarnesene dimers, the purified farnesane composition further comprisesfarnesane dimers, the hydrogenated versions of farnesene dimers. Theamount of dimers is typically less than about 0.5% based on total weightof the farnesane. In one embodiment, the amount of farnesene dimers isabout 0.05%, 0.07%, 0.09%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3% or 0.5% basedon total weight of the farnesane. In one embodiment, the amount offarnesane dimers is about 0.2% based on total weight of the farnesane.

In certain embodiments, the product of hydrogenation of amicrobial-derived farnesene mixture comprises unsaturated farnesane. Incertain embodiments, the product comprises a monounsaturated farnesane.In certain embodiments, the product comprises farnesane and anunsaturated farnesane. In further embodiments, the product comprisesabout 0.1 to 50%, 0.1 to 25%, or 0.1 to 10% monounsaturated farnesane bytotal weight of the product. In still further embodiments, the productcomprises about 0.1% monounsaturated farnesane. In additionalembodiments, the product comprises about 10 to 99.9%, 20 to 99.9%, 50 to99.9%, 50 to 99%, or 50 to 90% farnesane by total weight of the product.In still additional embodiments, the product comprises at least about99.9% farnesane by total weight of the product.

In certain embodiments, a process provided herein comprises selectivehydrogenation of farnesene to reduce one, two, three or four doublebonds in farnesene. In one embodiment, a process yields a combination ofhydrogenated farnesene products. In one embodiment, a product obtainedin the hydrogenation process comprises a combination of farnesane andone or more monounsaturated farnesane products. In certain embodiments,a product comprises a monounsaturated farnesane in an amount from about0.1 to 50% by total weight of the product. In certain embodiments, theamount of monounsaturated farnesane in a product is about 0.1, 1, 10, 25or 50% by total weight of the product.

While the processes and systems provided herein have been described withrespect to a limited number of embodiments, the specific features of oneembodiment should not be attributed to other embodiments of theprocesses or systems. No single embodiment is representative of allaspects of the methods or systems. In certain embodiments, the processesmay include numerous steps not mentioned herein. In certain embodiments,the processes do not include any steps not enumerated herein. Variationsand modifications from the described embodiments exist.

It is noted that the processes for generation of hydrogenatedmicrobial-olefins are described with reference to a number of steps. Incertain embodiments, these steps can be practiced in any sequence. Incertain embodiments, one or more steps may be omitted or combined butstill achieve substantially the same results. The appended claims intendto cover all such variations and modifications as falling within thescope of the claimed subject matter.

All publications and patent applications mentioned in this specificationare herein incorporated by reference to the same extent as if eachindividual publication or patent application was specifically andindividually indicated to be incorporated by reference. Although theclaimed subject matter has been described in some detail by way ofillustration and example for purposes of clarity of understanding, itwill be readily apparent to those of ordinary skill in the art in lightof the teachings herein that certain changes and modifications may bemade thereto without departing from the spirit or scope of the appendedclaims.

EXAMPLE Example 1

This example describes the purification of farnesene that was producedby farnesene producing yeast strain A.

The yeast cells were separated from the fermentation broth using acontinuous disk stack nozzle centrifuge (Alfa Laval DX 203 B-34). Inaddition to removing the cells, this step also served to concentrate thebio-organic compound in a smaller volume. For this particular yeaststrain, a twenty fold concentration resulted in a composition that wasapproximately half farnesene and half fermentation medium. So for atwenty fold concentration, approximately 95% of the volumetric flowexited the centrifuge from the nozzles (cells+liquid) as waste whileapproximately 5% of the volumetric flow was captured as concentratedbio-organic composition.

This composition when allowed to settle or centrifuged, separated intothree distinct phases. The top layer comprised primarily the immiscibleolefin. The middle layer comprised emulsion formed by the cells, theimmiscible olefin and water. The bottom layer comprised the aqueousfermentation medium.

The pH of the concentrated composition was adjusted to pH 8.3 using 5 NNaOH, followed by incubation at about 30° C. for approximately one hour.The concentrated composition (pH˜8.3) was then subjected toliquid/liquid separation using the same centrifuge. Table 1 details theamounts of the bio-organic compound in each of the three phases(bio-organic compound layer; emulsion; and the aqueous layer) of thebasic concentrated bio-organic composition.

TABLE 1 liquid/liquid recovery of the concentrated composition at pH 8.3Layer % of farnesene bio-organic 82% (1.15 L) Emulsion  8% Aqueous 10%

The farnesene purity was 94.9% (w/w). The total acid number as measuredby ASTM D 664 was 0.9 mg KOH/g.

Example 2

This example describes further purification of farnesene from Example 1.

The farnesene was incubated with 0.4% w/w calcium hydroxide (e.g., AcrosOrganics, >98% pure, Cat. No. 21918000) for 2.5 hours at ambienttemperature. This results in precipitation of various impurities whichcan be removed by various methods including centrifugation andfiltration to yield a farnesene composition in which the organic acidsthat were extracted during the purification are neutralized. If desired,this neutralized composition can be further purified, for example, bydistillation. Table 2 describes the total acid number and glycerincontent of the various compositions.

TABLE 2 TAN & Glycerin content Ca(OH)₂ Analytical Test Crude treatedDistilled TAN (mg KOH/g of immiscible 0.5 0 0 olefin) Sterols 0.31 0.315none detected Glycerin % w Free Glycerin none none none detecteddetected detected Total Glycerin 0.048 0.047 0.007 Monoglyceride 0.0860.087 0.027 Diglyceride 0.017 0.014 none detected Triglyceride 0.2130.205 none detected

TABLE 3 Hydrocarbon quantification Ca(OH)2 Crude treated DistilledHydrocarbon (% area) (% area) (% area) Farnesene 98.46 98.47 98.56Zingiberene 0.286 0.285 0.287 Bisabolene 0.198 0.198 0.197 FarneseneEpoxide 0.193 0.194 0.193 Bisabolol 0 0.1 0 Farnesol Isomer 0.414 0.420.414 Farnesol 0.357 0.354 0.351 Squalene 0 0 0 Farnesene Dimer 0 0 0Ergosterol 0 0 0

TABLE 4 Trace Metals Ca(OH)₂ Crude treated Distilled Metal/Element (ppm)(ppm) (ppm) Boron 4 2 3 Calcium <1 134 <1 Chromium <1 <1 1 Magnesium 3 4<1 Sodium <3 <3 <3 Nickel <1 <1 1 Phosphorous 6 6 <1 Lead 1 1 1 Silicon6 6 2 Zinc 1 1 1 Antimony <1 <1 1 Following metals are <1 ppm: Silver,aluminum, barium, copper, iron, molybdenum, tin, vanadium

The calcium hydroxide treatment reduces the total acid number withoutsignificantly affecting the impurity profiles of the other components ofthe composition with the exception of increased calcium. However, thehigh levels of calcium can be fully removed by other purificationmethods such as flash distillation.

Example 3

This example describes purification of the crude olefin composition to apurified olefin composition using alumina. This purification method alsoserves to neutralize the organic acids that are present in the crudeolefin composition.

Alumina sorbent is regenerated prior to use by heating at 250° C. for atleast two hours. The crude olefin composition is brought to roomtemperature and is mixed with granular alumina (e.g., Selexsorb CDX) at10% w/v of the bio-organic compound and mixed overnight. The mixture isthen filtered by 0.45 μm filter and treated with 0.01% phenolicantioxidant such as 4-tert-butylcatechol.

When this method is used to purify the farnesene composition fromExample 1, the resulting purified farnesene composition has a total acidnumber of 0 mg KOH/g.

Example 4

This example describes the hydrogenation of limonene in a batch reactor.

Twenty five mL samples of limonene (FloraChem, >98% limonene) werehydrogenated to various extents in batch reactors at 100° C. and 50psig, over 50 mg 5% Pd/C (Alfa Aesar). Six samples were hydrogenated tovarious extents, and the compositions of the products are shown in FIG.10, as determined by GC analysis. As shown by FIG. 10, the compositionshifts from less saturated to more-saturated species as the reactionprogresses. The final product composition in this example after“complete” saturation was primarily two isomers of p-menthane, with ˜9%p-cymene and ˜1% dimethyloctane. The concentration of aromatic p-cymenein the “saturated” product of limonene hydrogenation has been found tobe a function of catalyst type, temperature, pressure, and reaction timeor LHSV (for flow reactors). The results are shown in FIG. 10.

Example 5

This example describes the hydrogenation of limonene in a fixed bedreactor using a palladium catalyst.

Limonene (FloraChem, >98% limonene) was blended with p-menthane orp-menthane/p-cymene mixtures to dilute the feed to 5-50% limonene, andwas fed to a fixed bed of 1 L of 0.3% Pd/Al₂O₃ extrudate obtained fromJohnson-Matthey, at flow rates of 21-82 g/min. This is approximatelyequivalent to a reactor LHSV of ˜1.6-6.2 L liquid/L cat/h or processLHSV of ˜0.06-0.9 L limonene/L cat/h. The liquid feed was fed at roomtemperature, and warmed as a result of heat of reaction. The liquid feedand hydrogen were blended and fed to the top of a tubular reactor, sothat it was operated in concurrent downflow. Tempered water at 80° C.was added to the middle section of the reactor to maintain the maximumtemperature in the reactor at 150° C. or less. The reactor pressure wasmaintained at 50-90 psig. The excess hydrogen in the reactor effluentwas maintained at 3.6-6.5 slpm. The product compositions are shown inTable 5.

TABLE 5 limonene hydrogenation products Feed flow Reactive feed ratePressure Dimethyl concentration g/min LHSV psig octane p-menthanep-menthene p-cymene limonene  5% 21 1.6 50 10% 21 1.6 50 0.7% 89% 0.3%9.2% 0.3% 15% 21 1.6 50 0.8% 84% 1.2% 13.2% 20% 24 1.8 50 0.9% 87% 11.0%25% 24 1.8 50 1.0% 86% 12.0% 30% 24 1.8 50 0.9% 85% 13.1% 35% 24 1.8 500.9% 83% 14.6% 35% 24 1.8 50 0.9% 83% 15.0% 43% 24 1.8 50 1.0% 80% 17.7%50% 24 1.8 50 1.0% 78% 0.7% 20.0% 25% 24 1.8 50 1.0% 86% 12.0% 25% 413.1 50 0.9% 81% 0.2% 17.0% 25% 64 4.8 50 1.0% 78% 0.9% 19.0% 25% 82 6.250 0.9% 74% 2.9% 21.0% 25% 82 6.2 90 1.0% 79% 0.6% 18.0%

Example 6

This example describes the hydrogenation of limonene in a fixed bedreactor using a nickel catalyst.

Limonene (FloraChem, >98% limonene) was blended with p-menthane orp-menthane/p-cymene mixtures to dilute the feed and was fed to a fixedbed of 1 L of 20% Ni Al₂O₃ extrudate obtained from Johnson-Matthey. Feedconcentration of limonene was 13-50%, and feed flow rate was 30-104g/min. The reactor LHSV was 2.3-7.8 L liquid/L cat/h, and the processLHSV was 0.3-2.0 L limonene/L cat/h. Tempered water was added to thecenter section of the reactor to maintain the maximum temperature at150° C. or less. Reactor pressures of 50-310 psig were utilized, andhydrogen effluent flow rate was maintained at 2.5-6.5 slpm. The productcomposition is shown below as a function of operating conditions. Theproduct composition was substantially different than what was observedfor 0.3% Pd/Al₂O₃. As shown in Table 6, measured p-cymene concentrationwas zero in almost all of the cases shown, demonstrating aromatichydrogenation activity, since the recycled liquid feed diluent containedp-cymene at the beginning of the test series. No olefinic unsaturatedspecies were observed in the tests shown.

TABLE 6 Limonene product compositions Feed flow Reactive feed ratePressure Dimethyl concentration g/min LHSV Psig octane p-menthanep-menthene p-cymene limonene 13% 30 2.3 50 1.2% 99% 25% 30 2.3 50 1.1%99% 35% 30 2.3 50 1.2% 99% 50% 30 2.3 50 1.2% 99% 25% 40 3.0 55 1.1% 98%25% 78 5.9 58 1.1% 99% 25% 104 7.8 47 1.1% 92.0%   6.5% 25% 100 7.5 1011.1% 99% 25% 100 7.5 200 1.1% 99% 25% 99 7.4 310 1.1% 99%

Mass balance tests were performed during hydrogenation while using 1 Lof 20% Ni/Al₂O₃ extrudate obtained from Johnson-Matthey, while feeding60 g/min of 25% limonene/p-menthane. This corresponds to a reactor LHSVof 4.5 L liquid/L cat/h or a process LHSV of 1.1 L limonene/L cat/h.Reactor pressure was maintained at 45-55 psig, temperature wasmaintained at <150° C., and excess hydrogen in the reactor effluent wasmaintained at 5.5-7.0 slpm. Mass of the feed liquid was recordedrepeatedly before and after operation for several hours. Mass of liquidrecovered from the reactor effluent during the same time period wasrecorded. A mass increase of 0.76% is expected for completehydrogenation of 25% limonene/p-menthane. The results are shown in theTable 7.

TABLE 7 MB1 MB2 MB3 MB4 SUM feed start 11250 16300 9700 11960 feed end2500 2110 2080 2500 Processed 8750 14190 7620 9460 40020 Recovered 887014680 7610 9670 40830 mass increase 120 490 −10 210 810 overall massincrease 2.02%

The overall observed mass increase was 2.0%. The difference betweenexpected and observed mass increase was probably due primarily to errorcaused by temporal variations in liquid holdup within the reactorsystem. This observed mass increase indicates that there was nomeasurable loss of liquid feed mass to side reactions such ashydrocracking.

Example 7

This example describes the hydrogenation of farnesene on a pilot scale.

Microbial-derived farnesene, which had been distilled with a wiped-filmdistillation apparatus, and which was stabilized with 100 ppmw4-tert-butylcatechol (“p-TBC”), was fed to a fixed bed reactor incocurrent downflow with excess hydrogen. The fixed bed reactor contained1 L of 20% Ni/Al₂O₃ extrudate obtained from Johnson-Matthey. The liquidfeed rate was 9.6 L/h, and the liquid composition was 10-15% farnesenein recycled farnesane. The reactor LHSV was 9.6 L liquid/L cat/h, andthe process LHSV was 0.96 to 1.4 L farnesene/L cat/h. The reactor jacketwas maintained at 150° C. by heat transfer fluid. The reactor wasmaintained at 500 psig. Excess hydrogen flow in the effluent wasmaintained at >1 slpm. GC analysis showed no measurable residual olefinsin the product. Br index measurement was performed by Intertek CalebBrett according to ASTM D2710, and results for samples from two 5-galcarboys of product yielded measured Br indices of only 8 and 10 mgBr/100 g liquid, indicating that residual unsaturation was negligible.

TABLE 8 Hydrogenation Conditions Liquid feed Feed Process ReactorHydrogen flow concentration LHSV LHSV feed Temperature (° C.) Pressure(psig) Sam- rate (L farnesene/ (L farnesene/ (L liquid/ rate Bath 1 6Up- Down- ple Time (L/h) L Liquid feed) L cat/h) L cat/h) (sipm) SP(top) 2 3 4 5 (bot) stream stream #  9:15 9.6 10% 0.96 9.6 7 150 128 195174 164 158 150 503 500 2 10:25 9.6 10% 0.96 9.6 7 150 118 202 180 168160 151 503 500 3 14:20 9.6 15% 1.44 9.6 10 150 123 233 193 174 163 150503 500 7 15:20 9.6 15% 1.44 9.6 10 150 124 231 192 173 162 150 503 5008 16:21 9.6 15% 1.44 9.6 10 150 124 241 195 175 163 152 503 500 9 21:269.6 15% 1.44 9.6 10 150 140 246 195 173 162 151 504 501 38 22:19 9.6 15%1.44 9.6 10 150 140 246 195 173 162 151 503 500 39 23:16 9.6 15% 1.449.6 10 150 140 246 195 173 162 151 503 500 40

Example 8

This example describes the hydroprocessing of 5% farnesene with anunfinished diesel fuel containing 1.1 wt. % sulfur. The unfinisheddiesel contained 1.2 wt. % (12,000 ppmw) S, 100 ppmw N, andapproximately 31 wt. % aromatics. The 10%-90% boiling range was 210°C.-370° C. based on simulated distillation.

A NiMoS catalyst (Albemarle) was activated by sulfiding withdimethyldisulfide. To establish a baseline, unfinished diesel wasintroduced to the reactor at LHSV=2.3, and was processed at 340° C. and650 psig. Hydrogen was fed with the liquid feed at an H₂/oil ratio of300 N m3H₂/m3 liquid feed (1,500 scf H2/bbl liquid). The reactortemperature profile and gas effluent composition were monitored, and thesample of unfinished diesel was processed for 72 hours. The sample ofunfinished diesel was desulfurized from 12,000 ppmw 5 to 13-20 ppmw Sunder these processing conditions, and was denitrogenated from 100 ppmwN to 0.3-0.4 ppmw N. The Br number of the feed decreased from 1.4 to<0.5 in the process, and total aromatics content decreased from about 31wt % to about 21 wt %. Aromatics reduction was substantial for di- andtri-aromatics, and negligible for mono-aromatics. The total hydrogenconsumption was about 57 N m3H₂/m3 liquid feed, or 350 scf H₂/bblliquid. Measurements of the effluent gas indicated that it containedapproximately 2.2 vol % H₂S, corresponding roughly to complete removalof the 1.2 wt % S from the feed liquid. The effluent gas also containedapproximately 0.1 vol % propane and heavier hydrocarbon fragments,corresponding to a total loss of ˜0.1% of the liquid feed tohydrocracking side reactions.

After 72 hours on stream, the liquid feed stream was switched fromunfinished diesel to a sample containing 5 wt. % farnesene (inunfinished diesel). Reactor temperature and pressure were maintained at340° C. and 650 psig, and the hydrogen:oil ratio was held constant at300 N m3H₂/m3 liquid feed (1,500 scf H₂/bbl liquid). The reactor was runfor 120 hours under these conditions. The farnesene-containing samplewas desulfurized from 1.2 wt % S down to 25-32 ppmw S during the courseof the 120 hours test. The S content in the effluent appeared to bedrifting upwards slowly during the test from 25 to 32 ppmw, and noeffort was made to decrease the S content of the effluent by adjustingoperating conditions. The Br number of the farnesene-containing sampleprior to hydroprocessing was substantially higher than that ofunfinished diesel alone due to the presence of 5% farnesene, and wasmeasured as 9.9. The Br number of the farnesene-containing sample wasdecreased to <0.5 during the hydroprocessing, and complete conversion offarnesene to saturated C15 was observed with serial GC×GC analysis. Thehydrogen consumption increased from the 57 N m3H₂/m3 liquid feed (350scf H₂/bbl liquid) observed for the unfinished diesel sample to 66 Nm3H₂/m3 liquid feed (400 scf H₂/bbl liquid) for the farnesene-containingsample, due to the additional hydrogen requirement for farnesenehydrogenation. Co-processing the farnesene had no measurable impact onhydrodenitrogenation activity or hydrodearomatization activity, as theeffluent concentrations of N and aromatics were approximately the samefor both samples. There was no measurable change in hydrocrackingactivity based on effluent gas concentrations of propane and C6+ speciesbetween the two samples. In addition, hydrocracking losses remainedconstant at about 0.1% for both samples.

The NiMoS catalyst was removed and examined for carbon deposits afterboth samples were hydroprocessed. Elemental analysis showedconcentrations of 7.3 wt % C and 12.1 wt % S, typical values observedfor NiMoS hydroprocessing catalysts. This result indicated that therewas no substantial increase in carbon deposition onto the catalyst fromhydroprocessing the farnesene-containing sample.

Example 9

This example describes the performance of hydrogenation catalyst PRICATNI HTC500RP 1.2 mm.

The reactor was charged with 25 cm3 PRICAT Ni HTC500RP 1.2 mm catalystin 4 discrete beds separated by coarse SiC (0.5-1.1 mm) again thecatalyst interparticle void was filled with fine grade SiC (0.1-0.3 mm,0.6 gSiC·g_(cat) ⁻¹).

The catalyst was activated under the following reduction conditions:

Gas: H2 (100%)

Gas flow rate: 50 l·hr-1

Pressure: 40 psig

Temperature: Ambient—120° C. (5° C.·min-1)

-   -   120° C. (60 min dwell)    -   120-230° C. (1.67° C.·min-1)    -   230° C. (60 min dwell)    -   Cool to first reaction temperature.

The catalyst performance at various temperatures and LHSVs of 5%farnesene in decane (at 500 psig) are summarized in Table 9.

TABLE 9 Bromine index of reactor exit samples from various hydrogenationruns. LHSV 10 LHSV 20 LHSV 40 Temperature Bromine Index 100 — 2300 4200140 — 750 2400 175 <100 200 800 220 — <100 170

Gas samples were also taken and analyzed to investigate what, if any,cracking reactions occurred. Table 10 summarizes the results.

TABLE 10 Gas analysis in ppm Process Conditions Temp LHSV Reactor Exit -Gas Analysis (ppm) (° C.) (hr⁻¹) Methane Ethane Propane Butane Pentane175 10 4607 28 52 32 10 99 20 84 4 10 18 10 141 20 368 7 8 15 10 175 201950 18 37 30 10 175 20 2087 18 35 29 10 175 20 2181 16 35 27 10 220 206194 85 121 53 11 100 40 61 4 9 17 10 140 40 249 6 7 13 8 175 40 1499 1531 28 10 175 40 1597 13 27 23 9 220 40 4808 57 97 48 10

Modifying the feed to 5% farnesene in farnesane made little differencein the bromine index of the resulting product at the reactor's exit. Itwas determined that hydrogenation under the following conditions: 175°C., LHSV 20 hr-1, 500 psig, and 5% farnesene feed resulted in a productwith a bromine index of 200-300 with a mono-olefin content <0.5%. Inaddition, the catalyst showed no significant change in bromine index atstandard conditions after 350 hrs on-line under these conditions.

Example 10

The discharged catalyst in Example 9 was characterized to see how thecatalyst had been modified. The catalyst was discharged in threeportions—top, middle, and bottom of the reactor. The top and middlesamples were analyzed by TGA to determine the decomposition temperatureof the carbon species. Results show no loss of nickel from the catalystand no significant loss of nickel surface area. A small amount of sulfurhas been observed on the top and middle samples at 0.06 and 0.1%respectively. For both samples, all of the weight loss was observedbefore 500° C., with the maximum weight loss at around 300° C. which isindicative of a long chain hydrocarbon. No carbon build was observed(e.g. no coking) on the discharged catalyst, however up to 4 wt %hydrocarbon was found which was attributed to long chain hydrocarbonsand which were not removable by extraction.

The examples set forth above are provided to give those of ordinaryskill in the art with a complete disclosure and description of how tomake and use the claimed embodiments, and are not intended to limit thescope of what is disclosed herein. Modifications that are obvious topersons of skill in the art are intended to be within the scope of thefollowing claims. All publications, patents, and patent applicationscited in this specification are incorporated herein by reference as ifeach such publication, patent or patent application were specificallyand individually indicated to be incorporated herein by reference.

What is claimed is:
 1. A method of stabilizing a microbial-derivedolefin composition comprising: a) separating immiscible olefin from amixture comprising an aqueous solution, microbial cells and immiscibleolefin thereby forming a crude olefin composition; b) purifying thecrude olefin composition thereby forming a purified olefin composition;and c) adding a phenolic antioxidant to the purified olefin compositionto form a stabilized purified microbial-derived olefin composition,wherein the phenolic antioxidant is a phenol derivative containing anunfused phenyl ring with one or more hydroxyl substituents, and ispresent in an amount that is at least 0.0001% by weight of stabilizedpurified microbial-derived olefin composition.
 2. The method of claim 1that further comprises adding a phenolic antioxidant to the crude olefincomposition.
 3. The method of claim 1, wherein the purification step isselected from fractional distillation, flash distillation, adsorption,liquid chromatography, solvent extraction and a combination thereof. 4.The method of claim 1, wherein the purification step comprises removingor reducing monoglycerides, diglycerides, and triglycerides in the crudeolefin composition.
 5. The method of claim 1, wherein the purificationstep comprises removing or reducing ergosterol or squalene in the crudeolefin composition.
 6. The method of claim 1, wherein the immiscibleolefin is farnesene and it is present in at least about 50%, 60%, 70%,80%, 90% 93%, 95%, 97%, 99% or greater by weight of the immiscibleolefin.
 7. The method of claim 6, wherein the immiscible olefin furthercomprises zingiberene, bisabolene, 10,11-dihydro-10,11-epoxyfarnesene,farnesene dimers, farnisol or a combination thereof.
 8. The method ofclaim 1, wherein the phenolic antioxidant is a polyphenol.
 9. The methodof claim 1, wherein the phenolic antioxidant is a monophenol.
 10. Themethod of claim 1, wherein the phenolic antioxidant is selected from3-tert-butyl-4-hydroxyanisole; 2-tert-butyl-4-hydroxyanisole;2,4-dimethyl-6-tert-butylphenol; and 2,6-di-tert-butyl-4-methylphenol.11. The method of claim 1, wherein the phenolic antioxidant is acatechol.
 12. The method of claim 11, wherein the phenolic antioxidantis 4-tert-butylcatechol.
 13. The method of claim 1, wherein the phenolicantioxidant is present in at least about 0.0001% by weight of thestabilized microbial-derived olefin composition.
 14. The method of claim1, wherein the phenolic antioxidant is present in at least about 0.001%by weight of the stabilized microbial-derived olefin composition. 15.The method of claim 2, wherein the amount of phenolic antioxidant is atleast about 0.005% by weight of the resulting crude olefin composition.16. The method of claim 1 further comprising reacting the immiscibleolefin with hydrogen in the presence of a hydrogenation catalyst suchthat hydrogen saturates at least one double bond in the olefin.
 17. Themethod of claim 16, wherein the hydrogenation reaction occurs at atemperature that is greater than room temperature.
 18. The method ofclaim 16, wherein the hydrogenation reaction occurs at a temperaturethat is greater than about 100° C.
 19. A stabilized microbial-derivedolefin composition prepared by the method of claim 1, wherein thestabilized microbial-derived olefin composition comprises: a) animmiscible olefin in an amount at least about 93% by weight of thecomposition; and b) a phenolic antioxidant, wherein the phenolicantioxidant is a phenol derivative containing an unfused phenyl ringwith one or more hydroxyl substituents in an amount at least about0.0001% by weight of the composition.
 20. The stabilizedmicrobial-derived olefin composition of claim 19, wherein the phenolicantioxidant is at least about 0.001% by weight of the composition. 21.The stabilized microbial-derived olefin composition of claim 19, whereinthe phenolic antioxidant is at least about 0.005% by weight of thecomposition.
 22. The stabilized microbial-derived olefin composition ofclaim 19, wherein immiscible olefin comprises farnesene.
 23. Thestabilized microbial-derived olefin composition of claim 22, wherein thefarnesene is at least about 50%, 60%, 70%, 80%, 90% 93%, 95%, 97%, 99%or greater by weight of the composition.
 24. The stabilizedmicrobial-derived olefin composition of claim 19, wherein the immiscibleolefin comprises an impurity selected from zingiberene, bisabolene,10,11-dihydro-10,11-epoxyfarnesene, farnesene dimers, farnisol and acombination thereof.
 25. The stabilized microbial-derived olefincomposition of claim 24, wherein the impurity is present in an amount ofat least about 0.05% by weight of the composition.
 26. The stabilizedmicrobial-derived olefin composition of claim 19, wherein the phenolicantioxidant is selected from: resveratrol;3-tert-butyl-4-hydroxyanisole; 2-tert-butyl-4-hydroxyanisole;2,4-dimethyl-6-tert-butylphenol; 2,6-di-tert-butyl-4-methylphenol; and4-tert-butylcatechol.
 27. The stabilized microbial-derived olefincomposition of claim 19, wherein the amount of phenolic antioxidant isat least about 0.005% by weight of the composition.
 28. The method ofclaim 16, wherein the hydrogenation reaction occurs at a temperaturethat is greater than about 100° C.
 29. The method of claim 16, whereinthe immiscible olefin is part of the crude olefin composition.
 30. Themethod of claim 16, wherein the immiscible olefin is part of thepurified olefin composition.
 31. The method of claim 16, wherein theimmiscible olefin is part of the stabilized purified olefin composition.32. The method of claim 16, wherein the immiscible olefin comprisesfarnesene.
 33. The method of claim 16, wherein the immiscible olefinfurther comprises a phenolic antioxidant.
 34. The method of claim 33,wherein the phenolic antioxidant is selected from: resveratrol;3-tert-butyl-4-hydroxyanisole; 2-tert-butyl-4-hydroxyanisole;2,4-dimethyl-6-tert-butylphenol; and 2,6-di-tert-butyl-4-methylphenoland 4-tert-butylcatechol.
 35. A purified farnesene composition preparedby the method of claim 6, wherein the purified farnesene compositioncomprises: a) a microbial-derived mixture comprising farnesene in anamount that is equal to or greater than about 93% by weight of thecomposition and the following compounds each of which is present in anamount that is equal to or greater than about 0.1% by weight:bisabolene, zingiberene, farnesol, and farnesene expoxide; and, b) aphenolic antioxidant, wherein the phenolic antioxidant is a phenolderivative containing an unfused phenyl ring with one or more hydroxylsubstituents in an amount that is at least about 0.001% by weight.
 36. Apurified farnesane composition prepared by the method of claim 6,wherein the purified farnesene composition comprises farnesane in anamount that is equal to or greater than about 93% by weight of thecomposition and the following compounds each of which is present in anamount that is equal to or greater than about 0.1% by weight: bisabolaneand tetradecane.